CN102680782A

CN102680782A - Method for calculating high-frequency signal frequency by utilizing low-frequency clock source

Info

Publication number: CN102680782A
Application number: CN201210187825XA
Authority: CN
Inventors: 项春亮; 梁剑; 齐良颉
Original assignee: DONGGUAN BOYONG ELECTRONIC TECHNOLOGY Co Ltd; DONGGUAN XIANGFENG ELECTRONIC TECHNOLOGY INDUSTRIAL Co Ltd
Current assignee: Dongguan Boyong Electronic Technology Co., Ltd.
Priority date: 2012-06-08
Filing date: 2012-06-08
Publication date: 2012-09-19

Abstract

The invention discloses a method for calculating a high-frequency signal frequency by utilizing a low-frequency clock source, which belongs to the field of the measurement of the signal frequency. The method comprises the steps of selecting an initial mark and an end mark of a system clock source of low-frequency of the known data through a mark unit, defining a determined test period T through the initial mark and the end mark, identifying the initial mark and the end mark of the system clock source through a detection unit, counting a level variation signal of an inputted signal to be detected by utilizing a counting unit, and finally calculating and outputting a frequency value of the inputted signal to be detected through a calculation and output unit. Due to the adoption of the method, not only is the frequency detection system simplified, but also the power consumption of the frequency detection system is simultaneously reduced.

Description

A kind of method of calculating the high-frequency signal frequency with the low-frequency clock source

Technical field

The present invention relates to the measurement of signal frequency, relate in particular to a kind of method of calculating the high-frequency signal frequency with the low-frequency clock source.

Background technology

According to Nyquist's theorem, in the transfer process of carrying out analog/digital signal, as SF f _SmaxGreater than highest frequency f in the input signal _Max2 times the time, the sampling after digital signal intactly kept the information in the original input signal.About the frequency computation part method of input signal, common employing is higher than frequency input signal and samples and count the accuracy that could guarantee result of calculation in the high frequency clock source of twice at least in the existing scheme.If frequency input signal to be detected is higher, then the clock source frequency also can double in the detection module, has increased the power consumption of frequency detecting system, has increased the complicacy of frequency detecting system simultaneously.

Summary of the invention

Technical matters to be solved by this invention is to the above-mentioned deficiency that exists in the prior art, and a kind of simplification frequency detecting system is provided, and reduces the method with low-frequency clock source calculating high-frequency signal frequency of frequency detecting system power dissipation simultaneously.

A kind of method with low-frequency clock source calculating high-frequency signal frequency of the present invention, realize through following steps:

(1), the system clock source of a given frequency, input signal to be detected, indexing unit, detecting unit, counting unit and the calculating output unit of a unknown frequency are provided; Said indexing unit, detecting unit, counting unit and calculating output unit electrically connect successively; Said indexing unit input end is in order to insert said system clock source, and said detecting unit input end is in order to insert said input signal to be detected;

(2), said indexing unit is chosen the initial markers and the end mark of said system clock source; The initial markers of said system clock source and end mark define a definite test period T; Said detection is to the marginal point of the initial markers that is in said system clock source; Transmit signal simultaneously and give said counting unit, the level variable signal of said detection input signal to be detected is with the counting condition as said counting unit;

(3), said detection is to the marginal point of the end mark that is in said system clock source; Said detecting unit stops to detect the level variable signal of input signal to be detected; Transmitting signal simultaneously stops to count for said counting unit, said counting unit and the count value N when keeping stopping to count;

(4), said calculating output unit calculates the frequency of input signal to be detected, utilizes rolling counters forward numerical value of N and definite test period T in the counting unit to be divided by, the frequency that obtains input signal to be detected is N/T.

Among embodiment, when said counting unit satisfied in each counting condition, the counter in the said counting unit added one therein.

Among embodiment, said counting unit is when beginning to count therein, and said counting unit initial value is 0.

Among embodiment, said discrepancy signal to be detected has the highest frequency limits value therein, is determined by the hardware performance that said detection system adopted, if N/T is not more than the highest frequency limits value, said calculating output unit is successfully exported the result; Then successfully calculate the frequency of input signal to be detected; If N/T is greater than the highest frequency limits value, the output result of then said calculating output unit is shown as mistake.

In sum; A kind of method with low-frequency clock source calculating high-frequency signal frequency of the present invention is chosen the initial markers and the end mark of low-frequency system clock source of given data through indexing unit; And define a definite test period T by initial markers and end mark; Cooperate detecting unit that the initial markers and the end mark of system clock source are discerned, utilize counting unit that the level variable signal of input signal to be detected is begun counting simultaneously, at last through calculating the frequency values that output unit calculated and exported input signal to be detected; Not only simplify the frequency detecting system, reduced the power consumption of frequency detecting system simultaneously.

Description of drawings

Fig. 1 is the structure principle chart of indexing unit of the present invention, detecting unit and counting unit.

Fig. 2 is the sequential chart of synchronous mode of the present invention.

Embodiment

For further understanding characteristic of the present invention, technological means and the specific purposes that reached, function, the present invention is described in further detail below in conjunction with accompanying drawing and embodiment.

As depicted in figs. 1 and 2, a kind of method with low-frequency clock source calculating high-frequency signal frequency of the present invention, realize through following steps:

(1) frequency being provided is the system clock source 10 of P KHz, input signal to be detected 20, indexing unit 30, detecting unit 40, counting unit 50 and the calculating output unit 60 that a frequency is the X megahertz; Said indexing unit 30, detecting unit 40, counting unit 50 and calculate output unit 60 and electrically connect successively; Said indexing unit 30 input ends are in order to insert said system clock source 10, and said detecting unit 40 input ends are in order to insert said input signal to be detected 20;

(2) said indexing unit 30 is chosen the initial markers and the end mark of said system clock source 10; The initial markers of said system clock source 10 and end mark define a definite test period T; Said detecting unit 40 detects the marginal point of the initial markers that is in said system clock source 10; Transmit signal simultaneously and give said counting unit 50, said detecting unit 40 detects the rising edge or the negative edge of input signal 20 to be detected, with the counting condition as said counting unit 50; When said counting unit 50 satisfied in each counting condition, the counter in the said counting unit 50 added one;

(3) said detecting unit 40 detects the marginal point of the end mark that is in said system clock source 10,

Said detecting unit 40 stops to detect the rising edge or the negative edge of input signal 20 to be detected, transmits signal simultaneously and gives said counting unit 50, and said counting unit 50 stops counting; Said counting unit 50 is when beginning to count, and said counting unit 50 initial value are 0; Said counting unit 50 after stopping counting, the count value N when said counting unit 50 keeps stopping to count, promptly in definite test period T, counting unit 50 has received the input signal to be detected 20 of the X megahertz in N cycle;

(4) frequency of 60 pairs of input signals 20 to be detected of said calculating output unit is calculated, and utilizes rolling counters forward numerical value of N and definite test period T in the counting unit 50 to be divided by, and the frequency that promptly obtains input signal 20 to be detected is X megahertz=N/T; Discrepancy signal 20 to be detected has the highest frequency limits value, is determined by the hardware performance that said detection system adopted, if N/T is not more than the highest frequency limits value, said calculating output unit is successfully exported the result; Then successfully calculate the frequency of input signal 20 to be detected; If N/T is greater than the highest frequency limits value, the output result of then said calculating output unit is shown as mistake.

The frequency P KHz of the system clock source 10 that the present invention adopted is a given data, confirms that test period T can set as the case may be, so that the time period that detecting unit 40 can accurately be discerned is as the criterion.

The specific embodiment of the invention is following; Choose the system clock source 10 of 10KHz; Indexing unit 30 carries out initial markers and end mark to system clock source 10 in definite test period T=1ms; At this moment, the initial markers of system clock source 10 is set at rising edge, and the end mark of system clock source 10 is set at rising edge equally; When detecting unit 40 detects the initial markers of system clock source 10; Detecting unit 40 detects the rising edge or the negative edge of input signal 20 to be detected; Simultaneously the counter in the counting unit 50 is when the rising edge of each input signal 20 to be detected or falling edge, and the output count value adds one; When detecting unit 40 detected the end mark of system clock source 10, counting unit 50 stopped counting and stored count value N, supposes N=10000, and calculate and output X megahertz=10000/1ms=10MHz through calculating output unit 60 this moment; 60 output results are shown as mistake if 10MHz, calculates output unit greater than the highest frequency limits value of detection system.

In sum; A kind of method with low-frequency clock source calculating high-frequency signal frequency of the present invention is chosen the initial markers and the end mark of low-frequency system clock source 10 of given data through indexing unit 30; And define a definite test period T by initial markers and end mark; Cooperate the initial markers and the end mark of 40 pairs of system clock sources 10 of detecting unit to discern, utilize the level variable signal of 50 pairs of input signals 20 to be detected of counting unit to begin counting simultaneously, at last through calculating the frequency values that output unit 60 calculated and exported input signal 20 to be detected; Not only simplify the frequency detecting system, reduced the power consumption of frequency detecting system simultaneously.

The above embodiment has only expressed several kinds of embodiments of the present invention, and it describes comparatively concrete and detailed, but can not therefore be interpreted as the restriction to claim of the present invention.Should be pointed out that for the person of ordinary skill of the art under the prerequisite that does not break away from the present invention's design, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection domain of patent of the present invention should be as the criterion with accompanying claims.

Claims

1. the method with low-frequency clock source calculating high-frequency signal frequency is characterized in that, realizes through following steps:

2. require described a kind of method with low-frequency clock source calculating high-frequency signal frequency according to right 1, it is characterized in that: when said counting unit satisfied in each counting condition, the counter in the said counting unit added one.

3. require described a kind of method with low-frequency clock source calculating high-frequency signal frequency according to right 1, it is characterized in that: said counting unit is when beginning to count, and said counting unit initial value is 0.

4. require described a kind of method of calculating the high-frequency signal frequency with the low-frequency clock source according to right 1; It is characterized in that: said discrepancy signal to be detected has the highest frequency limits value; Hardware performance by said detection system adopted determines; If N/T is not more than the highest frequency limits value, said calculating output unit is successfully exported the result; Then successfully calculate the frequency of input signal to be detected; If N/T is greater than the highest frequency limits value, the output result of then said calculating output unit is shown as mistake.