CN205333734U - Measuring -signal frequency and signal time interval's digital frequency meter - Google Patents
Measuring -signal frequency and signal time interval's digital frequency meter Download PDFInfo
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- CN205333734U CN205333734U CN201620076508.4U CN201620076508U CN205333734U CN 205333734 U CN205333734 U CN 205333734U CN 201620076508 U CN201620076508 U CN 201620076508U CN 205333734 U CN205333734 U CN 205333734U
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- lmh6642ma
- operational amplifier
- control mcu
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Abstract
The utility model discloses a measuring -signal frequency and signal time interval's digital frequency meter, include that amplification and rectification circuit unit, counter cascade circuit unit, master control MCU unit, the frequency division is asked or circuit unit to and display element, amplification and rectification circuit unit linkage counter cascades circuit unit, and the counter cascades circuit unit connects master control MCU unit, and the frequency division is asked or circuit unit connects master control MCU unit, and master control MCU unit and display element connect. The amplification and rectification circuit unit treat the height finding frequently slightly the signal amplification shaping carries out, then cascade circuit unit through the counter and count the square signal after changing, master control MCU unit reads counter cascades circuit unit's counting value and shows through display element, furthermore, the utility model discloses can also utilize the frequency division to ask or circuit unit measures two signal time interval with the cycle same frequency to show at display element.
Description
Technical field
This utility model belongs to signal frequency meter technical field, is specifically related to a kind of digital frequency meter measuring signal frequency and signal interval。
Background technology
Society, is gradually increased the use of high-frequency signal, but for the measurement of high frequency small-signal, does not but have good measuring method, how to measure high frequency small-signal accurately, for the process of signal with use most important。
Utility model content
The purpose of this utility model is in that to overcome the deficiencies in the prior art, it is provided that a kind of digital frequency meter, and the frequency of high frequency small amplitude signal can be measured by accurately, simultaneously can also to two signal interval measurements of same cycle same frequency。
This utility model is achieved through the following technical solutions:
A kind of digital frequency meter measuring signal frequency and signal interval, asks or circuit unit including amplification and rectification circuit unit, enumerator cascade circuit unit, main control MCU unit, frequency dividing, and display unit；Amplification and rectification circuit unit linkage counter cascade circuit unit, enumerator cascade circuit unit connects main control MCU unit, and frequency dividing is asked or circuit unit connects main control MCU unit, main control MCU unit and display unit and connects；
Described amplification and rectification circuit unit includes the LMH6642MA operational amplifier for amplifying measured signal and for measured signal is shaped as the 2nd LMH6642MA operational amplifier of square-wave signal；
Described enumerator cascade circuit unit includes the 74HC590 chip of two panels cascade；
Described frequency dividing is asked or circuit unit adopts 74LS74 flip-flop chip and 74LS32 or door chip。
In technique scheme, main control MCU unit adopts MSP430F149 single-chip microcomputer。
In technique scheme, + IN the foot of the oneth LMH6642MA operational amplifier connects 0V voltage, the IN foot of the oneth LMH6642MA operational amplifier and the OUTPUT foot of a LMH6642MA operational amplifier connect, the IN foot of the oneth LMH6642MA operational amplifier is as measured signal input, the OUTPUT foot of the oneth LMH6642MA operational amplifier connects the IN foot of the 2nd LMH6642MA operational amplifier, + IN the foot of the 2nd LMH6642MA operational amplifier connects VCC and GND, the V of the 2nd LMH6642MA operational amplifier respectively through resistance—Foot connects GND, the V of the 2nd LMH6642MA operational amplifier+Foot connects VCC, and the OUTPUT foot of the 2nd LMH6642MA operational amplifier is as the outfan of the signal after amplification shaping。
In technique scheme, the signal output part of amplification and rectification circuit unit is connected to CCK and the RCK of two 74HC590 chips, the CCKEN of first order 74HC590 chip receives on main control MCU unit, the CCKEN of second level 74HC590 chip receives on the RCO of first order 74HC590 chip, and the RCO of second level 74HC590 chip receives on main control MCU unit；Eight delivery outlets of two-stage 74HC590 chip are all received on the I/O of main control MCU, and the CCLR of two 74HC590 chips receives on the same I/O mouth of main control MCU simultaneously。
Advantage of the present utility model and having the beneficial effect that
When measuring signal frequency, after measured signal amplifies shaping by the circuit that LMH6642MA operational amplifier is constituted, become square-wave signal, frequency dividing by outside extension counter 74HC590, it is the measurement of the main control chip MSP430F149 low frequency signal that can catch by high frequency signals, then displays via human-computer interaction interface。
When carrying out the measurement of two signal intervals of same cycle same frequency, two with frequency measured signal by or door 74LS32 be merged into new signal, by main control chip to its measure, the interval of fore-and-aft survey is made comparisons, draw the interval of two signals, and display。
Accompanying drawing explanation
Fig. 1 is structural representation of the present utility model。
Fig. 2 is the circuit diagram of the amplification and rectification circuit in this utility model。
Fig. 3 is the chip pin figure of the LMH6642MA operational amplifier of the amplification and rectification circuit in this utility model。
Fig. 4 is the circuit diagram of the enumerator cascade circuit in this utility model。
Fig. 5 is that the frequency dividing in this utility model is asked or the circuit diagram of circuit。
Fig. 6 is that two homogenous frequency signals are asked or principle of stacking figure。
Detailed description of the invention
The technical solution of the utility model is further illustrated below in conjunction with specific embodiment。
A kind of digital frequency meter measuring signal frequency and signal interval involved by this utility model, asks or circuit unit including amplification and rectification circuit unit, enumerator cascade circuit unit, main control MCU unit, frequency dividing, and display unit；Amplification and rectification circuit unit linkage counter cascade circuit unit, enumerator cascade circuit unit connects main control MCU unit, and frequency dividing is asked or circuit unit connects main control MCU unit, main control MCU unit and display unit and connects。
High frequency small amplitude signal to be measured is amplified and square wave shaping by amplification and rectification circuit unit, high frequency small amplitude signal to be measured is transformed to the square-wave signal (signal frequency before and after conversion will not change) of the higher magnitude that enumerator is capable of identify that, then passing through enumerator cascade circuit unit the square-wave signal after change is counted, main control MCU unit is read the count value of enumerator cascade circuit unit and is displayed by display unit；Additionally, this utility model can also utilize frequency dividing to ask or the circuit unit two signal interval measurements to same cycle same frequency, and display at display unit。
As shown in Figure 2, described amplification and rectification circuit unit includes the LMH6642MA operational amplifier U1 for amplifying measured signal and for measured signal is shaped as the 2nd LMH6642MA operational amplifier U2 of square-wave signal, + IN the foot of the oneth LMH6642MA operational amplifier connects 0V voltage, the IN foot of the oneth LMH6642MA operational amplifier and the OUTPUT foot of a LMH6642MA operational amplifier connect, the IN foot of the oneth LMH6642MA operational amplifier is as measured signal input, the OUTPUT foot of the oneth LMH6642MA operational amplifier connects the IN foot of the 2nd LMH6642MA operational amplifier, + IN the foot of the 2nd LMH6642MA operational amplifier connects VCC and GND respectively through resistance, and (namely+IN foot of the 2nd LMH6642MA operational amplifier connects VCC by resistance R4, + IN the foot of the 2nd LMH6642MA operational amplifier connects GND by resistance R5), the V of the 2nd LMH6642MA operational amplifier—Foot connects GND, the V of the 2nd LMH6642MA operational amplifier+Foot connects VCC, and the OUTPUT foot of the 2nd LMH6642MA operational amplifier is as the outfan of the signal after amplification shaping。
As shown in Figure 4, described enumerator cascade circuit unit includes the 74HC590 chip of two panels cascade (in order to process the high-frequency square-wave signal after converting, adopt 74HC590 chip, it can process the high-frequency signal of 55MHz, when frequency is high especially, if signal being counted in 1s, the 74HC590 chip of a piece of 8 can not complete, therefore the mode of cascade is adopted, two panels 74HC590 chip is carried out cascade, thus expanding to 16, the counting being just capable of high-frequency signal processes)。The signal output part of amplification and rectification circuit unit is connected to the CCK of two 74HC590 chips (when meeting progression, carry out a rising edge to count once) and RCK (during rising edge, data being stored in depositor), CCKEN (the chip Enable Pin of first order 74HC590 chip U3, just work during low level) receive in main control MCU, control whether to count, the CCKEN of second level 74HC590 chip U4 receives the RCO of first order 74HC590 chip, and (RCO is overflow position, low level is become when meter is full) on, the RCO of second level 74HC590 chip receives in main control MCU, as the full interrupt signal of meter；Eight delivery outlets of two-stage 74HC590 chip are all received on the I/O of main control MCU simultaneously, to read first order 74HC590 chip numerical value time, main control MCU (reads data terminal to the G of first order 74HC590 chip, low electricity frequency is effectively) low level, equally to mono-low level of G when in like manner reading the data of second level 74HC590 chip。The CCLR (clear terminal) of two 74HC590 chips receives on the same I/O mouth of main control MCU simultaneously, it is necessary to during to two counter O resets, and main control MCU is to CCLR (clear terminal) low level。
Main control MCU unit adopts MSP430F149 single-chip microcomputer be controlled and calculate, when needs measure, MSP430 sets low to the Enable Pin CCKEN of first order 74HC590 chip, proceed by and measure simultaneously to the reading data terminal low level of the first order, read Q7 (lowest order of data output end), if Q7 is high, namely first rising edge is run into, open intervalometer simultaneously, when timer travel to 0.5s, judge whether enumerator overflows (namely whether the RCO of second level 74HC590 chip becomes low level) and judge measured signal height frequency, if not overflowing (now judging that measured signal is as low frequency signal), then at enumerator when running into a rising edge, stop timing, stop counting simultaneously, now it is frequency with the time divided by the number of enumerator；If there being spilling (now judging that measured signal is as high-frequency signal), then allowing intervalometer go further 0.5s, during to gate time of 1s, stopping timing, stopping counting, count value now is the frequency of signal。
As shown in Figure 5, described frequency dividing is asked or circuit unit adopts 74LS74 flip-flop chip U5 and 74LS32 or door chip U6 to measure two signal intervals with cycle same frequency signal, wherein 74LS74 trigger is to carry out two divided-frequency to measured signal, reduces the frequency detection range input of same frequency different conditions measured signal (CLR1 and the CLR2 of 74LS74 be)；74LS32 or door are that two dephased same signals carry out " superposition " (Y1 of 74LS32 asks or new frequency signal outfan afterwards), this superposition is equivalent to asking or computing its amplitude, it is A or B referring to accompanying drawing 6, measured signal A and the waveform after measured signal B superposition；Measure the high level time T2 of signal after the high level time T1 and superposition first sending signal during measurement respectively, then deduct the difference of T1 with T2 and be the interval X to be measured of two signals。
The following is test data of the present utility model:
1) for voltage effective value for 100mV sinusoidal signal, several different sine wave freuqency measured results are in Table 1。
| Standard frequency (Hz) | 1 | 20 | 510 | 1K | 20K |
| Practical frequency (Hz) | 1.0001 | 20.0013 | 510.0156 | 1000.0817 | 20000.7660 |
| Relative error | 0.0001 | 0.000065 | 0.00003 | 0.000082 | 0.000038 |
| Standard frequency (Hz) | 100K | 1M | 10M | 33M | 100M |
| Practical frequency (Hz) | 100006 | 1000022 | |||
| Relative error | 0.00006 | 0.000022 |
Table 1
2) for voltage effective value be 100mV, frequency for 200Hz square-wave signal, show that several groups of time interval values and relative error are in Table 2。
| Standard time interval | 0.1μs | 10μs | 200μs | 1ms | 10ms | 50ms | 100ms |
| Elapsed time interval | 0.1010 | 10.0630 | 201.1070 | 1.0090 | 10.0571 | 50.5402 | 100.3610 |
| Relative error | 0.0100 | 0.0063 | 0.0055 | 0.0090 | 0.0057 | 0.0108 | 0.0036 |
Table 2
According to upper table test result, voltage range is measured the relative error maximum in 1～10MHz frequency range close to 1 × 10 at the sine wave of 10mV～1V by this utility model-4, mean error is about 6/100000ths；Mean error to time interval measurement is 0.73 × 10-2。
Above this utility model has been done exemplary description; should be noted that; when without departing from core of the present utility model, any simple deformation, amendment or other those skilled in the art can not spend the equivalent replacement of creative work to each fall within protection domain of the present utility model。
Claims (4)
1. the digital frequency meter measuring signal frequency and signal interval, it is characterised in that: include amplification and rectification circuit unit, enumerator cascade circuit unit, main control MCU unit, divide and ask or circuit unit, and display unit；Amplification and rectification circuit unit linkage counter cascade circuit unit, enumerator cascade circuit unit connects main control MCU unit, and frequency dividing is asked or circuit unit connects main control MCU unit, main control MCU unit and display unit and connects；
Described amplification and rectification circuit unit includes the LMH6642MA operational amplifier for amplifying measured signal and for measured signal is shaped as the 2nd LMH6642MA operational amplifier of square-wave signal；
Described enumerator cascade circuit unit includes the 74HC590 chip of two panels cascade；
Described frequency dividing is asked or circuit unit includes 74LS74 flip-flop chip and 74LS32 or door chip。
2. the digital frequency meter of measurement signal frequency according to claim 1 and signal interval, it is characterised in that: main control MCU unit adopts MSP430F149 single-chip microcomputer。
3. the digital frequency meter of measurement signal frequency according to claim 1 and signal interval, it is characterized in that :+IN the foot of a LMH6642MA operational amplifier connects 0V voltage, the IN foot of the oneth LMH6642MA operational amplifier and the OUTPUT foot of a LMH6642MA operational amplifier connect, the IN foot of the oneth LMH6642MA operational amplifier is as measured signal input, the OUTPUT foot of the oneth LMH6642MA operational amplifier connects the IN foot of the 2nd LMH6642MA operational amplifier, + IN the foot of the 2nd LMH6642MA operational amplifier connects VCC and GND respectively through resistance, the V of the 2nd LMH6642MA operational amplifier￣Foot connects GND, the V of the 2nd LMH6642MA operational amplifier+Foot connects VCC, and the OUTPUT foot of the 2nd LMH6642MA operational amplifier is as the outfan of the signal after amplification shaping。
4. the digital frequency meter of measurement signal frequency according to claim 1 and signal interval, it is characterized in that: the signal output part of amplification and rectification circuit unit is connected to CCK and the RCK of two 74HC590 chips, the CCKEN of first order 74HC590 chip receives on main control MCU unit, the CCKEN of second level 74HC590 chip receives on the RCO of first order 74HC590 chip, and the RCO of second level 74HC590 chip receives on main control MCU unit；Eight delivery outlets of two-stage 74HC590 chip are all received on the I/O of main control MCU unit, and the CCLR of two 74HC590 chips receives on the same I/O mouth of main control MCU simultaneously。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620076508.4U CN205333734U (en) | 2016-01-26 | 2016-01-26 | Measuring -signal frequency and signal time interval's digital frequency meter |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620076508.4U CN205333734U (en) | 2016-01-26 | 2016-01-26 | Measuring -signal frequency and signal time interval's digital frequency meter |
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| Publication Number | Publication Date |
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| CN205333734U true CN205333734U (en) | 2016-06-22 |
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| CN201620076508.4U Expired - Fee Related CN205333734U (en) | 2016-01-26 | 2016-01-26 | Measuring -signal frequency and signal time interval's digital frequency meter |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107271771A (en) * | 2017-06-28 | 2017-10-20 | 北京电子科技学院 | Low-voltage network carrier signal detecting system |
| CN109116107A (en) * | 2018-08-21 | 2019-01-01 | 山东中创软件商用中间件股份有限公司 | A kind of digital frequency meter |
| CN112730979A (en) * | 2020-12-24 | 2021-04-30 | 太原航空仪表有限公司 | STM 32-based equal-precision frequency measurement method |
-
2016
- 2016-01-26 CN CN201620076508.4U patent/CN205333734U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107271771A (en) * | 2017-06-28 | 2017-10-20 | 北京电子科技学院 | Low-voltage network carrier signal detecting system |
| CN109116107A (en) * | 2018-08-21 | 2019-01-01 | 山东中创软件商用中间件股份有限公司 | A kind of digital frequency meter |
| CN112730979A (en) * | 2020-12-24 | 2021-04-30 | 太原航空仪表有限公司 | STM 32-based equal-precision frequency measurement method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20160622 Termination date: 20190126 |