JP3169982B2 - Wireless receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio receiver having one antenna and a plurality of receiving systems.

[0002]

2. Description of the Related Art Conventionally, two different frequency bands (for example, a 144 MHz band and a
Hz band), and simultaneously receive one signal at a time, and use two different frequencies within the same frequency band.
Two signals (for example, 4 as the calling main channel)
There is provided a wireless receiver capable of simultaneously receiving a signal of 33.00 MHz and a signal of another frequency within the 430 MHz band.

An example of the structure of the conventional radio receiver will be described with reference to FIG. In FIG. 4, a signal received by an antenna 10 is split into two, and a first filter 12 and a 430 MHz filter that pass only a signal in a 144 MHz band.
And a second filter 14 that passes only band signals. The signal that has passed through the first filter 12 passes through a first switch 16 and is branched into two, one of which is supplied to a first high-frequency amplifier circuit 18 of a first receiving system, and the other of which is a fourth one.
The signal is supplied to the second high-frequency amplifier circuit 22 of the second reception system via the switch 26. The signal that has passed through the second filter 14 passes through the third switch 24 and is branched into two signals.
One is supplied to the second high-frequency amplifier circuit 22 and the other is supplied to the first high-frequency amplifier circuit 18 via the second switch 20. In addition, the first and second switches 16 and 20 are opened and closed in reverse to form a first signal switching circuit 28.
Similarly, the third and fourth switches 24 and 26 have their opening and closing operations reversely interlocked to form a second signal switching circuit 30.

The output of the first high-frequency amplification circuit 18 is mixed with a local oscillation signal oscillated from a first local oscillation PLL frequency synthesizer 34 by a first mixing circuit 32, and the mixed output is used as a first intermediate-frequency amplification signal. Circuit 36 is provided. Only the intermediate frequency signal is amplified and extracted by the first intermediate frequency amplification circuit 36 and supplied to the first demodulation circuit 38.
The audio signal is demodulated by the demodulation circuit 38. This audio signal is amplified by the first audio amplification circuit 40 and is amplified from the first speaker 42. Note that the first high-frequency amplification circuit 18
The system up to the speaker 42 forms a first reception system that can receive signals in both the 144 MHz band and the 430 MHz band.

[0005] Similarly, the second high-frequency amplifier circuit 2
2 is output to the second mixing circuit 44 in the second local oscillation PLL.
The signal is mixed with the local oscillation signal oscillated from the frequency synthesizer 46, and the mixed output is provided to the second intermediate frequency amplifier circuit 48. Only the intermediate frequency signal is amplified and extracted by the second intermediate frequency amplifying circuit 48, supplied to the second demodulation circuit 50, and demodulated into an audio signal by the second demodulation circuit 50. This audio signal is amplified by the second audio amplifier circuit 52 and is amplified from the second speaker 54. The second high-frequency amplifier circuit 22
144 MHz depending on the system from
A second receiving system capable of receiving signals in both the band and the 430 MHz band is formed.

In such a configuration, first, when one signal in the 144 MHz band is received by the first receiving system and one signal in the 430 MHz band is received by the second receiving system, the state shown in FIG. 4 is set. That is, switching data for closing the first switch 16 and opening the second switch 20 is given to the first signal switching circuit 28 from a central processing unit (not shown). Further, the third switch 2 is connected to the second signal switching circuit 30.
Switching data for closing the fourth switch and opening the fourth switch 26 is provided. At the same time, N data for receiving a predetermined signal in the 144 MHz band is given to the first local oscillation PLL frequency synthesizer 34 from the central processing unit, and a predetermined signal in the 430 MHz band is received in the second local oscillation frequency synthesizer 46. N data for performing Then, the 144 MHz band signal passed through the first filter 12 is given to the first high frequency amplifier circuit 18 via the first switch 16, and the 430 MHz band signal passed through the second filter 14 is passed through the third switch 24. The signal is provided to the second high-frequency amplifier circuit 22. Here, the frequencies of the intermediate frequency signals of the first and second receiving systems are made different to prevent spurious, and the local oscillation signals oscillated from the first and second local oscillation PLL frequency synthesizers 34 and 46 are: Each is set so that it is not included in the other frequency band.

When two signals having different frequencies within the 430 MHz band are simultaneously received by the first and second receiving systems, the central processing unit sends the first signal to the first signal switching circuit 28 (not shown). Switching data for opening the switch 16 and closing the second switch 20 is provided, and switching data for closing the third switch 24 and opening the fourth switch 26 are provided to the second signal switching circuit 30. At the same time, the central processing unit supplies appropriate N data to the first and second local oscillation PLL frequency synthesizers 34 and 46, respectively. Then, 430M passed through the second filter 14
After passing through the third switch 24, the signal in the Hz band is split into two, one of which is passed through the second switch 20 to the first.
The signal is supplied to the high-frequency amplifier circuit 18, and the other signal is supplied to the second high-frequency amplifier circuit 22.

When two signals having different frequencies within the 144 MHz band are simultaneously received by the first and second receiving systems, the central processing unit sends the first signal to the first signal switching circuit 28 (not shown). Switching data for closing the switch 16 and opening the second switch 20 is provided, and the second signal switching circuit 30 opens the third switch 24 to cause the fourth switch 2 to open.
6 is provided. At the same time, the central processing unit supplies appropriate N data to the first and second local oscillation PLL frequency synthesizers 34 and 46, respectively. Then, 144 MH passed through the first filter 12
After the z-band signal passes through the first switch 16, it is split into two, one of which is provided to the first high-frequency amplifier circuit 18, and the other of which is provided to the second high-frequency amplifier circuit 22 via the fourth switch 26. Can be

[0009]

In the conventional radio receiver shown in FIG. 4, when two signals in the same frequency band are simultaneously received by the first and second reception systems, the first and second receptions are performed. There is a problem that the reception sensitivity is reduced as compared with the case where signals of different frequency bands are received in the system.
This is because when signals in different frequency bands are received by the first and second receiving systems, the signals received by one antenna 10 are separated by the first and second filters 12 and 14 for each frequency band, While each signal is given to one receiving system, the first and second receiving systems have two signals in the same frequency band.
When two signals are received simultaneously, one signal separated for each frequency band is further divided into two and given to the first and second receiving systems, so that the energy of the signal given to each receiving system is This is because it is about half.

The present invention has been made in view of the circumstances of such a conventional radio receiver, and has been made so that two signals in the same frequency band can be received at the same time without lowering the reception sensitivity. It is intended to provide a receiver.

[0011]

In order to achieve the above object, a radio receiver according to the present invention splits a signal received by one antenna into a plurality of signals, and separates these split signals into each branch path. In a wireless receiver provided to the receiving system of each branch via a filter that passes only signals of different frequency bands, a signal switching circuit is provided on a signal path of a signal that has passed the filter of each branch. Provided,
The signal switching circuit includes a through circuit in which a signal passing through the filter is provided to a receiving system of the branch path, and a circuit in which the branched signal is provided to a plurality of the receiving systems via an amplifier circuit and a distribution circuit. And a circuit in which a signal that has passed through the filter can be switched to a circuit that is not provided to a receiving system of the branch path, and the amplification circuit compensates for signal attenuation caused by branching in the distribution circuit. Have been.

In addition, a signal received by one antenna is divided into a plurality of signals, and the branched signals are passed through filters for passing only signals in different frequency bands for each of the divided signals. In a radio receiver provided to each receiving system, a signal switching circuit is provided on a signal path of a signal that has passed through a filter of at least one branch path, and the signal that has passed through the filter is provided with a signal switching circuit. A through circuit provided to a receiving system, and a signal branched by an amplifier circuit and a distribution circuit can be switched to a circuit provided to each of the plurality of receiving systems. The amplification circuit compensates for the signal attenuation, and a switch circuit is provided in the signal path of the signal that has passed through the filter of the other branch path. And a through circuit signal passed through the filter is provided to the reception system of the branch path, the signal that has passed through the filter may be configured to be switched between the circuit which is not imparted to the reception system of the branch passage.

[0013]

According to the first aspect of the present invention, a plurality of signals within the same frequency band are respectively received by a plurality of reception systems.
When receiving signals one by one, the signal switching circuit of the receiving system is switched to a circuit that amplifies the signal of the frequency band to be received by the amplifier circuit and distributes the amplified output to the number of receiving systems by the distribution circuit. By appropriately setting the gain of the amplifier circuit, a signal can be given to each receiving system with energy equivalent to the energy of the signal received by the antenna. Then, the signals of different frequency bands are
At the time of reception by two reception systems, if the signal switching circuit is a through circuit, no deterioration in reception characteristics occurs.

In the wireless receiver according to the second aspect, when a plurality of signals in the same frequency band of at least one receiving system are received one by one in a plurality of receiving systems, The signal switching circuit of the receiving system is switched to a circuit that amplifies the signal passing through the filter of the receiving system by the amplifier circuit and distributes the amplified output to the number of the receiving systems by the distribution circuit, thereby appropriately adjusting the gain of the amplifier circuit. By setting, a signal can be given to each receiving system with energy equivalent to the energy of the signal received by the antenna. When signals of different frequency bands are respectively received by one receiving system, if both the signal switching circuit and the switch circuit are through circuits, no deterioration in reception characteristics occurs.

[0015]

1 and 2 show an embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 is a block circuit diagram showing a state in which two signals having different frequencies in a 430 MHz band are simultaneously received by two receiving systems in one embodiment of the wireless receiver of the present invention, and FIG. 144 MHz at the receiver
FIG. 7 is a block circuit diagram showing a state in which one signal in each of the band and the 430 MHz band is simultaneously received by each receiving system. 1 and 2, the same circuit blocks as those in FIG. 4 are denoted by the same reference numerals, and redundant description will be omitted.

In FIG. 1, the signal that has passed through the first filter 12 is given to a common terminal c of a first switch 60. One selection terminal a of the first switch 60 is connected to the first amplifier circuit 62, and the amplified output is connected to the first distribution circuit 6
4 given. One of the two signals branched by the first distribution circuit is supplied to one selection terminal a of the second switch 66, and the other is supplied to the second high frequency amplifier circuit 22.
The other selection terminals b and b of the first and second switches 60 and 66 are connected to each other, and the common terminal c of the second switch 66 is connected to the first high-frequency amplifier circuit 18. First and second
The switches 60 and 66 form a first signal switching circuit 68. The first and second switches 60 and 66 are connected to one of the common terminals c and c according to the switching data from the central processing unit. , A state where the common terminals c and c are both connected to the other selection terminals b and b, and a state where the common terminals c and c are not connected to any of the selection terminals.

The signal that has passed through the second filter 14 is supplied to a common terminal c of the third switch 70. One selection terminal a of the third switch 70 is connected to the second amplification circuit 7.
2 and the amplified output is supplied to the second distribution circuit 74. One of the signals branched into two by the second distribution circuit is given to one selection terminal a of the fourth switch 76,
The other is provided to the first high-frequency amplifier circuit 18. The other selection terminals b and b of the third and fourth switches 70 and 76 are connected to each other, and the common terminal c of the fourth switch 76 is connected to the second high-frequency amplifier circuit 22. Third and fourth
The switches 70 and 76 form a second signal switching circuit 78, and the third and fourth switches 70 and 76 are connected to one of the common terminals c and c according to the switching data from the central processing unit. , A state where the common terminals c and c are both connected to the other selection terminals b and b, and a state where the common terminals c and c are not connected to any of the selection terminals.

In this configuration, when two signals having different frequencies in the 430 MHz band are simultaneously received by the first and second receiving systems, the first and second signal switching circuits 68 are switched by the switching data from the central processing unit. , 78 are set to the states shown in FIG. That is, the first and second switches 60 and 66 are set so that the common terminals c and c are not connected to any of the selection terminals, and the third and fourth switches 60 and 66 are not connected to any of the selection terminals.
The switches 70 and 76 are set so that the common terminals c and c are both connected to one of the selection terminals a and a. Then, the output signal of the second filter 14 is supplied to the second amplifier circuit 72 via the third switch 70 and is amplified. The amplified output is branched into two by a second distribution circuit 74, one of which is provided to the first high frequency amplifier circuit 18, and the other is provided to the second high frequency amplifier circuit 22 via the fourth switch 76.
Here, by appropriately setting the gain of the second amplification circuit 72, the energy of the signal given to the first and second high-frequency amplification circuits 18 and 22 is equal to or larger than the output signal of the second filter 14. It can be a signal of energy. Therefore, two signals having different frequencies in the 430 MHz band can be simultaneously received by the first and second receiving systems without causing a decrease in receiving sensitivity.

In the first receiving system, 1 band of 144 MHz band is used.
430 MHz band in the second receiving system.
When the two signals are received, the first and second signal switching circuits 68 and 78 are set to the states shown in FIG. 2 according to the switching data from the central processing unit. That is, the first, second, third, and fourth switches 60, 66, 70, and 76 are connected to the common terminals c, c, c, and c, respectively.
b, b, and b. Then, a through circuit is formed in each of the first and second signal switching circuits 68 and 78, the output of the first filter 12 is directly supplied to the first high-frequency amplifier circuit 18, and the output of the second filter 14 is directly transmitted to the second high-frequency amplifier circuit 18. The high-frequency amplification circuit 22 is provided. Therefore, the reception characteristics of the wireless receiver are not deteriorated at all.

When two signals in the 144 MHz band are simultaneously received by the first and second receiving systems, the first and second switches 60 and 66 are connected to the common terminal c, though not shown.
It is sufficient that c is connected to one of the selection terminals a and a, and the third and fourth switches 70 and 76 are set so that the common terminals c and c are not connected to any of the selection terminals.

FIG. 3 is a block circuit diagram of another embodiment of the radio receiver according to the present invention. In FIG. 3, the same or equivalent circuit blocks as those in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description will be omitted.

In the embodiment shown in FIG. 3, the first amplifier circuit 62 and the first distribution circuit 64 of the embodiment shown in FIG.
In place of the first signal switching circuit 68, a switch circuit 80 that opens or closes according to switching data from the central processing unit is interposed between the filter 12 and the first high-frequency amplifier circuit 18. Further, the second signal switching circuit 78 is configured to control the third and fourth switches 7 according to the switching data from the central processing unit.
0, 76 are common terminals c, c are both one select terminals a,
The state can be set to two, that is, the state connected to a and the state where both of the common terminals c and c are connected to the other selection terminals b and b.

In such a configuration, as shown in FIG. 3, the switching circuit 80 is switched by the switching data from the central processing unit.
Is opened and the third and fourth switches 70 and 76 of the second signal switching circuit 78 are connected with the common terminals c and c to one of the selection terminals a and a, respectively. The signal that has been passed through the second filter 14 is amplified and divided into two, and is supplied to the first and second high-frequency amplifier circuits 18 and 22. Therefore, as in the embodiment shown in FIG. 1, two signals having different frequencies in the 430 MHz band can be simultaneously received by the two receiving systems.

Although not shown, the switching circuit 80 is closed by the switching data from the central processing unit, and the third and fourth switches 70 and 76 of the second signal switching circuit 78 are connected to the common terminal c, c are connected to the other selection terminals b, b, so that the first filter 1
The signal passed through the second filter 14 is directly supplied to the first high-frequency amplifier circuit 18, and the signal passed through the second filter 14 is directly supplied to the second high-frequency amplifier circuit 22. Therefore, similarly to the embodiment shown in FIG.
One signal can be received at a time in the Hz band.

In the above embodiment, the first and second
Each of the signal switching circuits 68 and 78 and the switch circuit 80 is shown using a mechanical switch, but is not limited to this, and it is needless to say that the semiconductor switch such as a diode may be used. Also, the frequency band to receive is
It is not limited to the combination of the 144 MHz band and the 430 MHz band, and the same or different appropriate frequency bands may be combined. Further, three or more reception systems may be provided so that three or more signals in the same frequency band can be simultaneously received. The audio signals output from the first demodulation circuit 38 of the first reception system and the second demodulation circuit 50 of the second reception system are given to one common audio amplification circuit, and a plurality of reception systems are provided. May be configured to share one audio amplifier circuit and speaker.

[0026]

Since the radio receiver of the present invention is constituted as described above, the following special effects can be obtained.

According to the first aspect of the present invention, a plurality of signals in the same frequency band of each receiving system are simultaneously received by a plurality of receiving systems without causing a decrease in receiving sensitivity. be able to. Then, when signals of different frequency bands are respectively received by one receiving system,
By switching each signal switching circuit to a through circuit, the reception characteristics of the wireless receiver do not deteriorate at all.

Further, in the radio receiver according to the present invention, a plurality of signals in the same frequency band of at least one receiving system can be simultaneously transmitted to a plurality of receiving systems without lowering the receiving sensitivity. Each can be received. And
When signals of different frequency bands are respectively received by one receiving system, the signal switching circuit and the switch circuit are switched to the through circuit, so that the receiving characteristics of the wireless receiver are not deteriorated at all.

[Brief description of the drawings]

FIG. 1 shows a radio receiver according to an embodiment of the present invention at 430 MHz.
FIG. 4 is a block circuit diagram showing a state in which two signals having different band frequencies are simultaneously received by two reception systems.

FIG. 2 shows a radio receiver of FIG.
FIG. 4 is a block circuit diagram showing a state in which one signal is received simultaneously in each reception system in the Hz band.

FIG. 3 is a block circuit diagram of another embodiment of the wireless receiver of the present invention.

FIG. 4 is a block circuit diagram illustrating an example of a conventional wireless receiver.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Antenna 18 1st high frequency amplification circuit 22 2nd high frequency amplification circuit 34 1st local oscillation PLL frequency synthesizer 46 2nd local oscillation PLL frequency synthesizer 60 1st switch 62 1st amplification circuit 64 1st distribution circuit 66 2nd switch 68 first signal switching circuit 70 third switch 72 second amplifier circuit 74 second distribution circuit 76 fourth switch 78 second signal switching circuit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-53-126809 (JP, A) JP-A-60-173933 (JP, A) JP-A-1-157131 (JP, A) JP-A-2- 63226 (JP, A) JP-A-63-309030 (JP, A) JP-A-4-157793 (JP, A) JP-A 56-19941 (JP, U) JP-A-3-6338 (JP, U) Japanese Utility Model 5-25847 (JP, U) Japanese Utility Model 5-25846 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04B 1/06 H04B 1/16 H04B 1/18 H04B 1/26

Claims (2)

(57) [Claims] 1. A signal received by one antenna is divided into a plurality of signals, and each of the divided signals is passed through a filter that passes only a signal in a different frequency band for each of the divided signals. In a wireless receiver provided to each receiving system, a signal switching circuit is provided in a signal path of a signal that has passed through a filter of each branch, and a signal that has passed through the filter is received by the signal of the branch. A through circuit provided to the system, a circuit in which a signal branched through an amplifier circuit and a distribution circuit is provided to each of the plurality of reception systems, and a signal passed through the filter is provided to the reception system of the branch path. The amplifier circuit compensates for the signal attenuation caused by the splitting in the distribution circuit. Line receiver. 2. A signal received by a single antenna is divided into a plurality of signals, and each of the divided signals is passed through a filter that passes only a signal in a different frequency band for each of the divided signals. In a radio receiver provided to each receiving system, a signal switching circuit is provided on a signal path of a signal that has passed through a filter of at least one branch path, and the signal that has passed through the filter is provided with a signal switching circuit. A through circuit provided to a receiving system, and a signal branched by an amplifier circuit and a distribution circuit can be switched to a circuit provided to each of the plurality of receiving systems. The amplification circuit compensates for the signal attenuation, and a switch circuit is provided on the signal path of the signal that has passed through the filter of the other branch path. It is characterized in that it can be switched between a through circuit in which a signal passing through a filter is provided to a receiving system of the branch and a circuit in which a signal passing through the filter is not provided to a receiving system of the branch. Radio receiver.