JPH08340276A - Judgement method for matched pulse and spread spectrum communication receiver - Google Patents

Abstract

PURPOSE: To prevent the erroneous judgement of matched pulses before synchronization acquisition completion and to prevent the decline of the detection probability of the matched pulses after the synchronization acquisition completion in a spread spectrum communication receiver for performing demodulation by using a correlation means by a matched filter. CONSTITUTION: A first comparator circuit 61 outputs first synchronization pulses (c) in the case of exceeding a first judgement reference value S1 and a second comparator circuit 62 outputs second synchronization pulses (e) in the case of exceeding a smaller second judgement reference value S2. A peak detection circuit 8 outputs third synchronization pulses (g) when the second synchronization pulses (e) are outputted in the short time period of a prescribed width ΔT. A pulse generation circuit 9 outputs extraction pulses (i) synchronized with the first synchronization pulses (c) in an initial stage and outputs the extraction pulses (i) synchronized with the third synchronization pulses (g) thereafter. A sampler 11 outputs the matched pulses (j) synchronized with the extraction pulses (i).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spread spectrum communication receiver for demodulating a spread spectrum signal (hereinafter also referred to as an SS signal), and more particularly to a spread spectrum communication for demodulating using a correlation means by a matched filter. It concerns the receiver.

[0002]

2. Description of the Related Art A conventional spread spectrum communication receiver includes a matched filter as one of means for demodulating a received SS signal. The matched filter has an input signal and a filter pattern (P
Since the cross-correlation value of N code) is output, a large output (matched pulse) is generated at the moment when the pattern of the input signal and the filter pattern match. When the input signal is continuous, the matched pulse appears at a constant time period, and the matched pulse is extracted to demodulate the SS signal.

In order to extract the matched pulse, it is necessary to determine whether or not the output of the matched filter is the matched pulse and detect its temporal position. As a method for determining a matched pulse, as disclosed in Japanese Patent Laid-Open No. 61-93746, it is determined whether or not the output of the matched filter exceeds a predetermined determination reference value. If it is determined that it is a matched pulse,
The timed position is detected, and the matched pulse is extracted according to the timing.

However, in an environment with interference, noise components other than the matched pulse may increase depending on the level of interference, in which case the S / N ratio of the output of the matched filter deteriorates. If the determination reference value is reduced in such a state, noise components other than the matched pulse may exceed the determination reference value and make an incorrect determination.
On the contrary, if the judgment reference value is increased, there is a problem that the matched pulse cannot be detected when the level becomes small due to the level fluctuation of the matched pulse itself, and the matched pulse detection probability decreases.

In this way, even if the judgment reference value is made small or large, there are problems, and therefore an effective technique capable of simultaneously solving such problems is desired. As such a technique, Japanese Patent Laid-Open No. 05-175934 discloses that the P of the output of the matched filter is output before the completion of the synchronization acquisition.
The peak value in the period of one cycle of the N code is compared with the determination reference value of the carrier detection circuit to determine whether or not the pulse is a matched pulse. There is disclosed a technique in which a narrow time width before and after the arrival of the peak value is predicted to be the peak value detection period.

According to the technique disclosed in Japanese Unexamined Patent Publication No. 05-175934, after the completion of the synchronous acquisition, even if the judgment reference value of the carrier detection circuit is set to a small value, an error due to a noise component exceeding the judgment reference value is certainly caused. The judgment can be prevented. Further, even before the completion of the synchronization acquisition, when the target SS signal is received, the determination is made based on the peak in the period of one cycle of the PN code, so even if the determination reference value is made small, erroneous determination is considerably prevented. it can.

[0007]

As described above, according to the technique disclosed in Japanese Patent Laid-Open No. 05-175934, the target S
When the S signal is being received, erroneous judgment can be considerably prevented even if the judgment reference value of the carrier detection circuit is reduced.
If the target SS signal is not received, the problem of erroneously determining a peak due to a noise component other than the matched pulse as a matched pulse cannot be solved when the determination reference value is reduced.

Further, even when the target SS signal is received, when the level of the matched pulse becomes small due to the relative level fluctuation of the received signal,
Since the peak due to the noise component may exceed the level of the matched pulse, there is a problem that an erroneous determination is made when the determination reference value is reduced. If the judgment reference value is increased to prevent such an erroneous judgment, the detection probability of the matched pulse decreases after the completion of the synchronous acquisition, and the target SS signal is received even though it is received. However, the problem that the judgment reference value may be increased or decreased may not be solved.

Generally, before the completion of synchronization acquisition, it is necessary to detect a matched pulse whose temporal position cannot be predicted at all. Therefore, it is important to prevent erroneous determination rather than increase the detection probability. After the synchronization acquisition is completed, the temporal position of the next matched pulse can be predicted, so that it is necessary to place an emphasis on increasing the detection probability.

Therefore, even if the above-mentioned two contradictory problems (erroneous determination and decrease in detection probability) cannot be solved at the same time, it is sufficient that they can be solved one by one before and after the completion of the synchronization acquisition.

The present invention has been made paying attention to such a point. It is possible to prevent erroneous determination of a matched pulse due to a noise component before the completion of the synchronous acquisition, and to perform a relative determination after the completion of the synchronous acquisition. It is an object of the present invention to provide a method and an apparatus capable of preventing a decrease in the detection probability of a matched pulse due to various level fluctuations.

[0012]

According to a method of determining a matched pulse in a spread spectrum communication receiver of claim 1, the correlation output of the matched filter is exceeded by comparison with a first determination reference value before completion of synchronization acquisition. In this case, it is determined to be a matched pulse, and after completion of the synchronous acquisition, it is determined to be a matched pulse when the correlation output is compared with a second determination reference value smaller than the first determination reference value and exceeded.

Further, in the matched pulse determination method according to a second aspect of the present invention, after the synchronous acquisition is completed, the peak value of the correlation output in a predetermined period including the time when the matched pulse appears is compared with the second determination reference value. If it exceeds the threshold, it is judged as a matched pulse. In the spread spectrum communication receiver according to claim 3, the correlation between the matched filter and the first comparing means for outputting the first comparison output when the correlation output of the matched filter exceeds the first determination reference value. Second comparing means for outputting a second comparison output when the output is compared with a second determination reference value smaller than the first determination reference value and exceeds the second determination reference value, and the first comparison before the completion of synchronization acquisition. An output signal is output as an extraction signal, and an extraction signal selection unit that outputs the second comparison output as an extraction signal after the completion of synchronization acquisition and a matched pulse extraction unit that extracts a matched pulse by the extraction signal are provided. I took it.

According to another aspect of the spread spectrum communication receiver of the present invention, the first comparison output is outputted when the correlation output of the matched filter is compared with the first judgment reference value and exceeds the first judgment reference value.
And a second comparing means for outputting a second comparative output when the correlation output of the matched filter is compared with a second judgment reference value smaller than the first judgment reference value and exceeds the second judgment reference value. After completion of capturing, the peak temporal position of the correlation output in a predetermined period including the time point at which the matched pulse appears is detected, and if there is the second comparative output at the temporal position of the peak, the peak that outputs the detection output Detection means,
Extraction signal selecting means for outputting the first comparison output as an extraction signal before the completion of the synchronization acquisition, and outputting the detection output as the extraction signal after the completion of the synchronization acquisition, and a matched pulse extraction for extracting a matched pulse by the extraction signal. And the means of being provided.

According to another aspect of the spread spectrum communication receiver of the present invention, comparing means for outputting an extraction signal when the correlation output of the matched filter is compared with the judgment reference value and exceeds the judgment reference value, and the judgment reference value is set before the completion of synchronization acquisition. The first judgment reference value,
After the completion of the synchronization acquisition, a judgment reference value changing means for setting the judgment reference value to a second judgment reference value smaller than the first judgment reference value and a matched pulse extracting means for extracting a matched pulse by the extraction signal are provided. I took the measure.

According to another aspect of the spread spectrum communication receiver of the present invention, comparing means outputs a comparison output when the correlation output of the matched filter is compared with the judgment reference value and exceeds the judgment reference value; The first judgment reference value,
A judgment reference value changing means for setting the judgment reference value to a second judgment reference value smaller than the first judgment reference value after the completion of the synchronization acquisition, and a predetermined period including a time point when the matched pulse appears after the completion of the synchronization acquisition. At the peak position of the correlation output in, the peak detection means for outputting the detection output if there is the comparison output at the time position of the peak, and outputs the comparison output as an extraction signal before the completion of synchronization acquisition. After the completion of the synchronous acquisition, the extraction signal selecting means for outputting the detection output as the extraction signal and the matched pulse extracting means for extracting the matched pulse by the extraction signal are provided.

[0017]

According to the matched pulse judging method of the present invention, before the completion of the synchronous acquisition, it is judged as a matched pulse when the correlation output of the matched filter is exceeded in comparison with the larger first judgment reference value. The peaks due to noise components and the like are ignored.

After the completion of the synchronous capture, if the correlation output is compared with the second judgment reference value smaller than the first judgment reference value and exceeds the second judgment reference value, it is judged as a matched pulse and is output. For example, even if the peak that should be a matched pulse becomes small, it is surely detected. Claim 2
According to the matched pulse determination method of (1), after the synchronous acquisition is completed, only the peak value of the correlation output in the predetermined period including the time when the matched pulse appears is compared with the second determination reference value. The existing peak is not judged as a matched pulse even if it exceeds the second judgment reference value.

According to the spread spectrum communication receiver of claim 3, the correlation output of the matched filter is the first comparing means for comparing with the first judgment reference value, and the second comparison value is smaller than the first judgment reference value. Is input to the second comparing means for comparing with the judgment reference value of, and the matched signal is extracted by the output of the first comparing means by the extraction signal selecting means before the completion of the synchronization acquisition, so that a peak due to a noise component or the like is generated. It will be ignored.

After the completion of the synchronous acquisition, the extracted signal selecting means extracts the matched pulse from the output of the second comparing means, so that even if the peak to be the matched pulse becomes small due to the level fluctuation or the like, the matched pulse is surely reduced. To be detected. According to the spread spectrum communication receiver of claim 4,
After the synchronization acquisition is completed, the peak detection means
Peaks of timing other than a predetermined period including the time when the matched pulse appears are excluded.

According to the spread spectrum communication receiver of claim 5, the judgment reference value compared with the correlation output in the comparison means is set to the second judgment reference value smaller than the first judgment reference value after the completion of the synchronization acquisition. Since it is changed, even smaller level peaks are detected. According to the spread spectrum communication receiver of claim 6, the judgment reference value compared with the correlation output in the comparison means is changed to the second judgment reference value smaller than the first judgment reference value after the completion of the synchronization acquisition. After the synchronization acquisition is completed, even a smaller level peak is detected. Then, after the completion of the synchronous acquisition, the peak detection means eliminates the peak at the timing other than the predetermined period including the time point at which the matched pulse appears. Therefore, the peaks other than the above timing are the second determination reference value. Even if it exceeds, it is not judged as a matched pulse.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a spread spectrum communication receiver used in a matched pulse determination method according to the present invention will be described in detail below with reference to FIGS.

In each figure, 1 is a spread spectrum communication receiver. Matched filter 2 receives the SS
A cross-correlation value between the signal and a predetermined filter pattern (PN code) is calculated and a correlation output a is output. The decision circuit 3 outputs a matched pulse j as a result of comparing the correlation output a of the matched filter 2 with the decision reference values of two types, large and small.
The data reproducing circuit 4 demodulates and reproduces the data based on the matched pulse j.

The structure of the judgment circuit 3 will be described. Arithmetic circuit 5
Outputs the squared correlation output a from the matched filter 2. The arithmetic circuit 5 may perform an arithmetic operation that takes an absolute value instead of the square. The first comparison circuit 61 compares the output b of the arithmetic circuit 5 with the first determination reference value S1 and indicates the temporal position when the output b of the arithmetic circuit 5 is larger than the first determination reference value S1. It outputs 1 sync pulse c and counter start signal d.

The second comparing circuit 62 compares the output b of the arithmetic circuit 5 with the second judgment reference value S2, and when the output b of the arithmetic circuit 5 is larger than the second judgment reference value S2, the temporal position thereof. And outputs the second synchronization pulse e. Here, the first determination reference value S1 is set to a value larger than the second determination reference value S2.

The counter 7 starts counting by the counter start signal d output from the first comparison circuit 61, and P
After a predetermined time T shorter than the cycle of the N code, a pulsed timing signal f having a predetermined width ΔT is output. For example, a timing signal f having a width of 3 chips from a time point shorter by one chip of the PN code to a time point longer by one chip than one cycle of the PN code.
Alternatively, the pulse output after the counting is finished after a predetermined time T which is slightly shorter than one cycle of the PN code is output as a timing signal f shaped into a pulse having a predetermined width ΔT by a one-shot multivibrator or the like.

The peak detection circuit 8 detects the temporal position of the peak of the correlation output a during the short period of the predetermined width ΔT of the timing signal f output from the counter 7, and performs the second synchronization at the detected temporal position of the peak. By performing a logical product process with the pulse e, it is checked whether or not the second synchronization pulse e is output at the same timing. If the second synchronization pulse e is output, the third synchronization pulse g indicating the peak temporal position is output, and at the same time, the correction signal h for correcting the timing of the counter 7 is output.

Further, the logical product process of the peak value of the correlation signal a detected by the timing signal f and the second synchronizing pulse e is performed, and the second value is obtained at the time position of the detected peak.
If the synchronization pulse e is not output, it is determined that the SS signal being received is interrupted, and the entire device is initialized. The pulse generation circuit 9 receives the first synchronization pulse c and the third synchronization pulse g, outputs an extraction pulse i synchronized with the first synchronization pulse c in the initial stage, and thereafter outputs the third synchronization pulse c.
It is configured to output the extraction pulse i synchronized with the synchronization pulse g. An example of the pulse generation circuit 9 is shown in FIG.
In the initial state where the flip-flop circuit 91 is reset, as shown in FIG.
, The logic element 92 to which the third synchronizing pulse g is input does not output. Since the flip-flop circuit 91 inverts the output at the rising edge of the first synchronizing pulse c, only the logic element 93 outputs the output thereafter.

The delay circuit 10 gives a delay equivalent to the delay of the extracted pulse i with respect to the correlation output a to the correlation output a and outputs the correlation output a '. The sampler 11 samples the correlation output a ′ output from the delay circuit 10 in synchronization with the extraction pulse i and outputs the matched pulse j. here,
The first comparing means of claim 3 corresponds to the first comparing circuit 61, the second comparing means corresponds to the second comparing circuit 62, and the extraction signal selecting means includes the counter 7, the peak detecting circuit 8 and the pulse. Corresponding to the generating circuit 9, the matched pulse extracting means corresponds to the sampler 11.

The first comparing means of claim 4 corresponds to the first comparing circuit 61, and the second comparing means is the second comparing circuit.
62, the peak detecting means corresponds to the counter 7 and the peak detecting circuit 8, and the extraction signal selecting means corresponds to the pulse generating circuit 9.
The matched pulse extraction means corresponds to the sampler 11.

In the above configuration, when the timing signal f is not output from the counter 7 and the initial state before the completion of the synchronization acquisition, that is, the first determination reference value S1 is not exceeded, Small second judgment reference value S
Even if the second sync pulse e is output every time the number exceeds 2, the third sync pulse g is not output due to the logical product process in the peak detection circuit 8.

However, when the first synchronization pulse c is output, the pulse generation circuit 9 outputs the extraction pulse i,
The correlation output a ′ is sampled by the sampler 11 and the matched pulse j is output. That is, only a peak value having a high level exceeding the first judgment reference value S1 is judged as a matched pulse.

Next, after the first synchronization pulse c and the counter start signal d are output and the synchronization acquisition is completed, the counter 7 starts counting and a predetermined time T after the timing of the next matched pulse is predicted. The timing signal f having the width ΔT is output, the peak is detected, and the second signal
By the logical product processing with the synchronization pulse e, the third synchronization pulse g
And the correction signal h are output.

Therefore, the pulse generation circuit 9 outputs the extracted pulse i, the correlation output a'is sampled by the sampler 11, and the matched pulse j is output. In addition,
The counter 7 corrects the count timing by the correction signal h. In this way, after the matched pulse j is once detected, if it is the expected timing, even a peak at a lower level is determined as a matched pulse, so that a high detection probability can be obtained. .

In this way, in the initial state before the completion of synchronization acquisition, only peaks exceeding the first judgment reference value S1 at a high level are judged as matched pulses, and therefore erroneous judgment of matched pulses due to noise components is made. It can be prevented. Further, after the completion of the synchronous acquisition in which the matched pulse is once detected, if it is in the vicinity of the expected timing, even a peak exceeding the smaller second judgment reference value S2 is judged as a matched pulse. It is possible to prevent the detection probability of the matched pulse from being lowered due to the temporary level fluctuation.

In this way, the conventional conflicting problems can be solved all at once.

FIG. 3 is a block diagram of the spread spectrum communication receiver of the second embodiment. In the second embodiment, the comparison circuit 63 compares the output b of the arithmetic circuit 5 with the determination reference value S3, and when the output b of the arithmetic circuit 5 exceeds the determination reference value S3, the time position is determined. The synchronizing pulse c'and the counter start signal d'shown are output. The change circuit 64 has a first
Of the first reference value S1 and a second reference value S2 smaller than the first reference value S1 are input, and the first reference value S1 is set as the reference value until the synchronizing pulse c ′ is input. It outputs to the comparison circuit 63 as S3, and the synchronizing pulse c '
After is input, the second determination value is replaced with the second determination value S1.
The determination reference value S2 of 1 is output to the comparison circuit 63 as the determination reference value S3.

Therefore, once the synchronizing pulse c ′ is detected, the output b of the arithmetic circuit 5 in the comparison circuit 63 is obtained.
Is compared with a second determination reference value S2 whose level is smaller than the first determination reference value S1, and if it exceeds, a synchronization pulse c '
Is output. Then, after a predetermined time T, the counter 7 outputs a timing signal f having a predetermined time width ΔT for predicting the timing of the next matched pulse, and this time width Δ
A peak is detected in T, and the third sync pulse g and the correction signal h are output by a logical product process with the sync pulse c ′.

In this way, after the completion of the synchronous acquisition, if it is near the expected timing (between T and T + ΔT), even a peak exceeding the smaller second judgment reference value S2 is regarded as a matched pulse. Since the determination is made, it is possible to prevent a decrease in the detection probability of the matched pulse due to a relative level change. Note that the other constituent elements in FIG. 3 have the same functions as the constituent elements in FIG.

Here, the comparing means of claim 5 is a comparing circuit.
63, counter 7, peak detection circuit 8, pulse generation circuit 9
Corresponding to, the judgment reference value changing means corresponds to the changing circuit 64,
The matched pulse extraction means corresponds to the sampler 11. The comparing means of claim 6 corresponds to the comparing circuit 63,
The judgment reference value changing means corresponds to the changing circuit 64, the peak detecting means corresponds to the counter 7 and the peak detecting circuit 8, the extraction signal selecting means corresponds to the pulse generating circuit 9, and the matched pulse extracting means corresponds to the sampler 11. are doing.

FIG. 4 is a block diagram of the spread spectrum communication receiver of the third embodiment. In the third embodiment, the matched pulse determination method according to claims 1 and 2 is realized by including a control circuit 66 using a microcomputer. In FIG. 4, the output b of the arithmetic circuit 5 is converted into a digital value by the AD conversion circuit 67 and input to the control circuit 66. The memory 68 has a program for controlling the control circuit 66 and a first program.
Necessary data such as the judgment reference value S1 and the second judgment reference value S2 are stored. If the output a of the matched filter is a digital signal, the AD conversion circuit 67 is naturally unnecessary.

The extraction pulse i is output at the timing determined by the control circuit 66 to be a matched pulse. The operation of the control circuit 66 will be described below with reference to the flowchart of FIG. First, before the completion of the synchronization acquisition, in step 1, when the output b is compared with the first determination reference value S1 and exceeds, the extraction pulse i is output and the process proceeds to step 2.

After the completion of synchronization acquisition, in step 2,
After measuring a predetermined time T shorter than one cycle of the PN code, the process proceeds to step 3. In step 3, the output b is compared with a second criterion value S2 smaller than the first criterion value S1. When the output b exceeds the second judgment reference value S2 within a predetermined time width ΔT, the extraction pulse i
Is output.

In this way, the matched pulse is mainly judged by the software processing and the extracted pulse i is output, and the matched pulse is extracted by the sampler 11 and the data reproducing circuit 4 is used to extract the data as in the first embodiment. Is played. In this case, since the determination is mainly performed by software processing, it is easy to improve the processing function and add various additional functions by changing the program and data.

[0045]

According to the determination method of the first aspect of the present invention, before the completion of the synchronous acquisition, it is determined as a matched pulse when the correlation output of the matched filter is exceeded by comparing with the larger first determination reference value. Since this is output as a result, it is possible to obtain the effect of preventing erroneous determination of the matched pulse due to the noise component.

After the completion of the synchronous acquisition, the correlation output is compared with the smaller second judgment reference value, so that it is possible to prevent the detection probability of the matched pulse from being lowered due to the relative level fluctuation. According to the determination method of the invention of claim 2, after the completion of the synchronous acquisition, the peak value of the correlation output and the second determination reference value are exceeded only in a predetermined period including the time when the matched pulse appears. In this case, since the matched pulse is determined, even if the second determination reference value is set to a small value, it is possible to obtain the effect of preventing the erroneous determination of the matched pulse due to the noise component.

According to the spread spectrum communication receiver of the third aspect of the present invention, before the completion of the synchronization acquisition, the extraction signal selecting means uses the output of the first comparing means exceeding the larger judgment reference value as the extraction signal. Since the matched pulse is extracted, it is possible to prevent the erroneous determination of the matched pulse due to the noise component. Also, after the synchronization acquisition is completed,
The extracted signal selecting means extracts the matched pulse by using the output of the second comparing means exceeding the smaller judgment reference value as the extraction signal, so that it is possible to prevent the detection probability of the matched pulse from decreasing due to relative level fluctuation. Is obtained.

In this way, the conventional conflicting problems can be solved all at once. According to the spread spectrum communication receiver of the invention of claim 4, the peak detection means compares the peak value of the correlation output with the second determination reference value only in a predetermined period including the time when the matched pulse appears. If it exceeds, it is determined as a matched pulse. Therefore, even if the second determination reference value is set to a small value, it is possible to obtain the effect of preventing erroneous determination of the matched pulse due to noise components.

According to the spread spectrum communication receiver of the fifth aspect of the present invention, the judgment reference value in the comparing means is the first judgment reference value before the completion of the synchronization acquisition, and the above-mentioned judgment reference value after the completion of the synchronization acquisition. Since the judgment reference value is changed to the second judgment reference value smaller than the first judgment reference value, only one comparing means is required, and the circuit configuration is simplified.

According to the spread spectrum communication receiver of the sixth aspect of the present invention, the peak detection means determines the peak value of the correlation output and the second judgment reference value only during a predetermined period including the time when the matched pulse appears. Since it is judged as a matched pulse when the comparison result is exceeded, the effect of preventing erroneous judgment of the matched pulse due to noise components can be obtained even if the second judgment reference value is set to a small value, and the judgment reference value in the comparison means is obtained. Before the completion of the synchronization acquisition, the determination reference value is changed to the first determination reference value, and after the completion of the synchronization acquisition, the determination reference value is changed to the second determination reference value smaller than the first determination reference value. Therefore, only one comparison means is required, and the circuit configuration can be simplified.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of a first embodiment of a spread spectrum communication receiver used in a determination method according to the present invention.

FIG. 2 is an explanatory diagram illustrating signals of respective units of the spread spectrum communication receiver according to the first embodiment.

FIG. 3 is a configuration diagram of a spread spectrum communication receiver in a second embodiment.

FIG. 4 is a configuration diagram of a spread spectrum communication receiver in a third embodiment.

FIG. 5 is a flowchart of a main part of a program for controlling the spread spectrum communication receiver according to the third embodiment.

FIG. 6 is a circuit diagram showing a main part of an example of a pulse generation circuit used in the spread spectrum communication receiver of the present invention.

[Explanation of symbols]

1 Spread Spectrum Communication Receiver 2 Matched Filter 61 First Comparison Circuit (First Comparison Means of Claims 3 and 4) 62 Second Comparison Circuit (Second Comparison Means of Claims 3 and 4) 63 Comparison Circuit (Claim) (Comparison means of claims 5 and 6) 64 Change circuit (determination reference value change means of claims 5 and 6) 7 Counter (extracted signal selection means of claim 3, peak detection means stage of claim 4, comparison of claim 5 Means, claim 6
Peak detecting means) 8. Peak detecting circuit (extracted signal selecting means according to claim 3,
Peak detecting means according to claim 4, comparing means according to claim 5, peak detecting means according to claim 6 9 pulse generating circuit (extracted signal selecting means according to claim 3,
Extraction signal selection means according to claim 4, comparison means according to claim 5, extraction signal selection means according to claim 6 11 Sampler (matched pulse extraction means) S1 First judgment reference value S2 Second judgment reference value S3 Judgment reference Value a Correlation output c First synchronization pulse (first comparison output) e Second synchronization pulse (second comparison output) g Third synchronization pulse i Extraction pulse (extraction signal) j Matched pulse

Claims (6)

[Claims] 1. A method for determining a matched pulse in a spread spectrum communication receiver using a matched filter as a demodulating means, wherein the correlation output of the matched filter is exceeded by comparison with a first determination reference value before completion of synchronization acquisition. If it is determined that the pulse is a matched pulse and the synchronous acquisition is completed, the correlation output is set to the first pulse.
The method for determining a matched pulse, which is characterized in that when it exceeds a second determination reference value smaller than the determination reference value, the determination is a matched pulse. 2. After completion of the synchronous acquisition, if the peak value of the correlation output in a predetermined period including the time point at which the matched pulse appears is compared with the second determination reference value, it is determined to be the matched pulse. The matched pulse determination method according to claim 1. 3. A spread spectrum communication receiver using a matched filter as demodulation means, wherein a first comparison output is output when a correlation output of the matched filter is compared with a first judgment reference value and exceeds the first judgment reference value. Comparing means for comparing the correlation output of the matched filter with a second judgment reference value smaller than the first judgment reference value, and outputting a second comparison output if the second comparison reference value is exceeded.
Extraction signal selecting means for outputting the first comparison output as an extraction signal before the completion of the synchronization acquisition and outputting the second comparison output as the extraction signal for the completion of the synchronization acquisition, and a matched pulse is extracted by the extraction signal. A spread spectrum communication receiver comprising: matched pulse extracting means. 4. A spread spectrum communication receiver using a matched filter as demodulation means, wherein a first comparison output is output when a correlation output of the matched filter is compared with a first judgment reference value and exceeds the first judgment reference value. Comparing means for comparing the correlation output of the matched filter with a second judgment reference value smaller than the first judgment reference value, and outputting a second comparison output if the second comparison reference value is exceeded.
After the completion of the synchronization acquisition, the temporal position of the peak of the correlation output in a predetermined period including the time point at which the matched pulse appears is detected, and if there is the second comparison output at the temporal position of the peak, the detection output is output. Peak detection means, extraction signal selection means that outputs the first comparison output as an extraction signal before the completion of synchronization acquisition, and outputs the detection output as an extraction signal after the completion of synchronization acquisition, and a matched pulse by the extraction signal. A spread spectrum communication receiver comprising: matched pulse extracting means for extracting. 5. A spread spectrum communication receiver using a matched filter as demodulation means, comparing means for outputting an extraction signal when the correlation output of the matched filter is compared with a judgment reference value, and before completion of synchronization acquisition. Is a first determination reference value, and after the completion of the synchronous acquisition, the determination reference value is a second determination reference value smaller than the first determination reference value. A spread spectrum communication receiver comprising: matched pulse extracting means for extracting a matched pulse from a signal. 6. A spread spectrum communication receiver using a matched filter as demodulation means, comparing means for outputting a comparison output when the correlation output of the matched filter is compared with a judgment reference value, and before completion of synchronization acquisition. And a determination reference value changing means for setting the determination reference value as a first determination reference value, and after the completion of the synchronization acquisition, the determination reference value as a second determination reference value smaller than the first determination reference value, and the synchronization acquisition. After completion, a peak detection unit that detects the temporal position of the peak of the correlation output in a predetermined period including the time when the matched pulse appears, and outputs the detection output if there is the comparison output at the temporal position of the peak, Extraction signal selecting means for outputting the comparison output as an extraction signal before the completion of the synchronization acquisition and outputting the detection output as an extraction signal after the completion of the synchronization acquisition, and the extraction signal selecting means. And a matched pulse extracting means for extracting a matched pulse.