外文翻譯--基于同步頻率測量的數(shù)字頻率計的設(shè)計方法（英文）

1、201O 2nd International Conference on Computer Technology and Development (ICCTD 2010) Design of Digital Frequency Meter Based on Synchronous Frequency Measurement Method Hong Qunhuan Song Shile Xiao Zhihong Faculty of

2、Electronic and Information Zhejiang Wanli University Ningbo, China zwuhqh@126.com Faculty of Electronic and Information Zhejiang Wanli University Ningbo, China 6286679@lqq.com Faculty of Electronic and Information Zhejia

3、ng Wanli University Ningbo, China jhxiaozh@hotmail.com Abstract-This paper introduces a design scheme of high­precision digital frequency meter based on synchronous frequency measurement method. We select Cypr

4、ess PsoCl Cy8C29466 as its core component, the whole design is flexible and simple, has very few peripheral devices and a high reliability. And meanwhile, we realize equal precision measurement of signals in differ

5、ent frequency ranges by sectional frequency measurement method. Keywords-synchronous frequency measurement method; high precision; PSoC; PSoC Designer I. INTRODUCTION Digital frequency meter is a common measurin

6、g instrument and it can be used not only in general simple measurement but also in other fields, such as teaching, scientific research and industrial control, etc. The precision and efficiency of frequency measurement of

7、ten determine the performance and benefit of instrument, meter or industrial control system, but the precision of frequency measurement has a direct relation with the scientificity and rationality of frequency mea

8、surement methods. There are two common frequency measurement methods, namely frequency measurement method and period measurement method. Frequency measurement method refers to recording the number of pulses of t

9、he measured signal N by a counter in a given gate time TO, thereby getting the frequency of the measured signal f=NrrO, the accuracy of the measurement method depends on gate time and counting value of counter and theref

10、ore it is relatively suitable for measuring high-frequency signals; period measurement method refers to measuring one cycle time T of the measured signal and then getting its frequency f=lrr, its measurement accurac

11、y depends on the timing precision of the system and therefore it is relatively suitable for measuring low-frequency signals. The precisions of frequency meter designed by the above two methods are not high and

12、the precisions of measured results for signals whose frequencies are different are different. A synchronous frequency measurement method proposed in this paper is used to solve the precision problem of frequency meter, i

13、t can eliminate ±1 counting error problem which limits the increase of measurement accuracy, thereby greatly 978-1-4244-8845-2/10/ $ 26.00 © 2010 IEEE 697 improving the accuracy and performance of frequen

14、cy measurement. II. PRINCIPLE OF SNCHRONOUS FREQUENCY MEASUREMENT METHOD Shown as Fig. 1, the basic principle of synchronous frequency measurement method is as follows: synchronously send measured signal Ix and system r

15、eference signal Is to two counters A and B for measuring in a given gate time, thereby getting two counting values Nx and Ns respectively and then get the frequency of the measured signal by calculation: (1) Figur

16、e 1. Schematic Diagram of System Composition When Using Synchronous Frequency Measurement Method The key of synchronous frequency measurement method is the synchronous enable control of two counters. In order to realize

17、 the complete synchronization of two counters, one synchronous controller is needed to be responsible for opening and closing the two counters synchronously. In order to improve counting precision, when the gate signal g

18、iven by system timer is opened, the two counters don't begin counting immediately until the rising edge of the measured signal comes. That is to say, after the control signal appears, the first pulse rising edge of t

19、he subsequent measured signal enables the two counters to begin counting. 2010 2nd International Conference on Computer Technology and Development (ICCTD 2010) 1 GIO 01 OlE 0 ???“-------“'“­““ Figure 4. Co

20、nfiguration Diagram of Digital Modules in CY8C29466 Basic configuration of various digital modules: Timer is an 8-bit backward timer (Timer8), clock is VC3 (93.75 KHz), period is 200, the value of comparand register is 1

21、00 and interrupt trigger condition is counting endpoint. The counter of measured signal is a 16-bit binary backward counter (Counter16), clock is external measured signal, enable signal is the high level produced by exte

22、rnal synchronous controller, period is the maximum value 65535 and interrupt trigger condition is comparative value. The counter of system reference signal is a 32-bit binary backward counter (Counter32), clock is double

23、 system clock, namely 48MHz, enable signal is the high level produced by external synchronous controller, period is 4294967295 and interrupt trigger condition is comparative value. B. Design afSystem Peripheral Circuit

24、In order to realize the equal precision measurement in different frequency bands, we select different gate times to measure the frequencies of signals in different frequency bands, namely sectional frequency measurement

25、method and concrete frequency band division and gate time selection scheme is shown as the following Tab. 1. TABLE!. ERROR ANALYSIS TABLE OF FREQUENCY MEASUREMENT Frequency Given Maximum Range Range of Gate Measnr

26、ement Remarks Gear Measured Time Error Signal O. 1Hz 10Hz lOs 2. 083X 10-9 2 10Hz?lKHz Is 2. 083X 10-8 The frequency of system 3 1KHz?100KHz O. Is 2. 083X 10-7 reference signal 4 100KHz?lOMHz 10ms

27、 2.083 X 10-6 is 48MHz Frequency band switch is realized by a simple 4-bit dial switch, one end of the dial switch is connected to a high level and the other end is connected to 110 port of CY8C29466, each switch outp

28、ut is connected with one LED as indicator light. When the system operates, it can be realized by calling sub-band sub-function. We select a D flip-flop as synchronous controller, because D flip-flop is triggered at the r

29、ising edge of the clock, D end is timing interrupt signal produced by the internal 699 timer (Timer8) of CY8C29466 chip and the clock is connected to the measured signal, when the gate signal of timer is opened and outpu

30、ts a high level to make D= 1, at the moment, if the measured signal has a rising edge, Q outputs a high level and makes the two counters Counter16 and Counter32 work. The display part is a character type liquid crystal

31、display and we use the single 110 port of main control chip CY8C29466 as the interface of industry standard HD44780ALCD controller. The interface is composed of 8 data bits, read/write (R/W), register selection “R

32、S“ and enable signal “E“ . Considering the number of character bits to be displayed and refresh speed, etc, a 4-bit interface mode is adopted in this design. The hardware circuit of frequency meter system is shown as F

33、ig. 5. Figure 5. Hardware Circuit Diagram of Frequency Meter System V. SYSTEM SOFTWARE DESIGN According to the principle of synchronous measurement and user module configuration in PSoC chip, this paper gives the desig

34、n scheme of system main program and the workflow diagram of main program is shown as Fig. 6. ?. 3 l ? . Lt “- “ L' t' n R I R2 R3 R4 ;:.<I) 330 330 JJO 330 ? I upell lWO COUtlTe1S r'ui! for c:n

35、ublc: ?ignsl) I EmJll!'s? loop w<Ji t; for illll“rrupt I Figure 6. Workflow Diagram of System Main Program In the main program design of CY8C29466 chip, after the system is powered up, its internal start-up file

36、 boot. asm initializes system programs, including C language global variable and interrupt vector table, after start-up is finished, the system operates normally. First, call frequency band selection subprogram to judge