CN201607486U - Digital frequency characteristic tester - Google Patents
Digital frequency characteristic tester Download PDFInfo
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- CN201607486U CN201607486U CN2010201202559U CN201020120255U CN201607486U CN 201607486 U CN201607486 U CN 201607486U CN 2010201202559 U CN2010201202559 U CN 2010201202559U CN 201020120255 U CN201020120255 U CN 201020120255U CN 201607486 U CN201607486 U CN 201607486U
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Abstract
The utility model relates to a digital frequency characteristic tester, which comprises a sweep frequency signal output, a sweep frequency signal input, two shaping amplifying circuits, a D trigger, a singlechip, a phase discriminator, an AND gate, a counter and a digital frequency synthesizer. An input end of the digital frequency synthesizer is connected with the singlechip, while an output end thereof is connected with an input end of the AND gate. The digital frequency characteristics tester can realize equal precision measurement under circuit network signal frequencies of different signal frequencies and has lower cost.
Description
Technical field:
The utility model relates to a kind of DIGITAL FREQUENCY characteristic tester.
Background technology:
Measure the amplitude-frequency and the phase-frequency characteristic of a circuit network system, generally will adopt frequency-characteristic measuring-testing instrument, i.e. sweep generator, analog sweep generator costs an arm and a leg, and is bulky, complicated operation, bring inconvenience to the user, can not satisfy user's requirement gradually.The DIGITAL FREQUENCY characteristic tester has replaced analog sweep generator to become the direction of research and design gradually.At present, the circuit block diagram of the DIGITAL FREQUENCY characteristic tester of prior art is as shown in Figure 1: it comprises swept-frequency signal output, the swept-frequency signal input, the swept-frequency signal that the circuit-under-test network is not promptly passed through in the swept-frequency signal input, the swept-frequency signal after the circuit-under-test network is promptly passed through in swept-frequency signal output, two shaping amplification circuits, d type flip flop, single-chip microcomputer, phase detector, with door, counter and clock signal input, described swept-frequency signal output is connected with the first shaping amplification circuit input end, the input end of the output termination d type flip flop of described first shaping amplification circuit, and described swept-frequency signal input is connected with the input end of second shaping amplification circuit, the input end of described second shaping amplification circuit is connected with the input end of the CP of d type flip flop end and phase detector, the output terminal of described phase detector is imported with clock signal and is connected with the input end of door, and described output terminal with door is connected with counter, and the output terminal sum counter of described d type flip flop all is connected with single-chip microcomputer.The principle of work of this DIGITAL FREQUENCY characteristic tester is: the input end of d type flip flop is by swept-frequency signal output conduct input, the CP end is by swept-frequency signal input conduct input, and the input and output of swept-frequency signal connect two input ends of phase detector, phase detector output obtains the phase information of signal, be the square-wave signal that maximum pulse width was 0.5 signal period, and obtain phase difference value by counter, judge then that by d type flip flop signal is leading still hysteresis again, if if d type flip flop Q end output 0, then be leading, if 1, then for lagging behind; If leading state illustrates that then signal lag has surpassed 0.5 signal period, at this moment, phase difference value should be the resulting count value of counter and adds 0.5 signal period value, promptly 180 °, if hysteretic state, then phase difference value is exactly the resulting count value of counter.
The phase-frequency characteristic of the circuit network system that this DIGITAL FREQUENCY characteristic tester frequency test signal is identical is accurately, when wanting the different circuit network of measuring-signal frequency, often added swept-frequency signal frequency is also different, but the DIGITAL FREQUENCY characteristic tester of this structure adds the immobilizing property of clock signal makes the accuracy of detection of low frequency circuit network be higher than the accuracy of detection of high-frequency circuit network far away, the instability that causes whole phase difference value to be measured, the precision that records phase difference value can change along with the variation of swept-frequency signal frequency, can not realize the equal precision measurement of the circuit network of unlike signal frequency.And, since clock frequency need with phase detector output with, therefore can be than the highest frequency of swept-frequency signal high many of the clock frequency that provides often are provided, in this case, signal under the low frequency circuit network, the counter records value will exceed a lot, causes the requirement of counter also high a lot, causes cost higher.
The utility model content:
The technical problems to be solved in the utility model is, overcomes existing technological deficiency, and the equal precision measurement under a kind of circuit network signal frequency that can realize the unlike signal frequency is provided, and lower-cost DIGITAL FREQUENCY characteristic tester.
Technical solution of the present utility model is, a kind of DIGITAL FREQUENCY characteristic tester is provided, it comprises swept-frequency signal output, the swept-frequency signal input, two shaping amplification circuits, d type flip flop, single-chip microcomputer, phase detector, with the door sum counter, described swept-frequency signal output is connected with the first shaping amplification circuit input end, the input end of the output termination d type flip flop of described first shaping amplification circuit, described swept-frequency signal input is connected with the input end of second shaping amplification circuit, and the input end of described second shaping amplification circuit is connected with the input end of the CP of d type flip flop end and phase detector, the output terminal of described phase detector be connected with the input end of door, described output terminal with door is connected with counter, and the output terminal sum counter of described d type flip flop all is connected with single-chip microcomputer, and it also comprises digital frequency synthesizer, the input end of described digital frequency synthesizer is connected with single-chip microcomputer, output terminal be connected with the input end of door.
After adopting said structure, the utlity model has following advantage:
Replaced the clock signal input as count signal with digital frequency synthesizer (being DDS), and can be by the output frequency of Single-chip Controlling DDS, at first, single-chip microcomputer receives the signal input and judges the swept-frequency signal frequency, single-chip microcomputer is according to the size of the output frequency of the size control DDS of swept-frequency signal frequency then, the frequency that finally reaches DDS output in the frequency sweep process can follow the swept-frequency signal frequency to do the frequency sweep action, make count pulse that signal under each frequency sweep frequency all has a respective frequencies with it with, like this by this corresponding relation of control, make the relation of the direct reacting phase potential difference of count value of counter, in the design, corresponding relation is: the frequency of DDS output is 360 times of swept-frequency signal frequency.Like this, phase difference value just can directly be reflected on the count value, and a count value unit is exactly the phase difference value of number of degrees.Because the swept-frequency signal frequency is to adjust according to the frequency of circuit-under-test network, and adopt this architecture digital formula frequency-characteristic measuring-testing instrument, no matter how the frequency of swept-frequency signal changes, the precision of its phase difference value all is identical, promptly realized the equal precision measurement under the circuit network signal frequency of unlike signal frequency, and make required counter only need to count above 180, very general on this counter market, cost is lower, thereby the cost of DIGITAL FREQUENCY characteristic tester is reduced.
Description of drawings:
Accompanying drawing 1 is the circuit block diagram of prior art DIGITAL FREQUENCY characteristic tester;
Accompanying drawing 2 is circuit block diagrams of the utility model DIGITAL FREQUENCY characteristic tester;
Accompanying drawing 3 is principle of work process flow diagrams of the utility model DIGITAL FREQUENCY characteristic tester.
Embodiment:
Below in conjunction with the drawings and specific embodiments the utility model is described in further detail.
As shown in Figure 2, the utility model provides a kind of DIGITAL FREQUENCY characteristic tester, it comprises swept-frequency signal output, the swept-frequency signal input, two shaping amplification circuits, d type flip flop, single-chip microcomputer, phase detector, with the door sum counter, described swept-frequency signal output is connected with the first shaping amplification circuit input end, the input end of the output termination d type flip flop of described first shaping amplification circuit, and described swept-frequency signal input is connected with the input end of second shaping amplification circuit, the input end of described second shaping amplification circuit is connected with the input end of the CP of d type flip flop end and phase detector, the output terminal of described phase detector be connected with the input end of door, described with the door output terminal be connected with counter, the output terminal sum counter of described d type flip flop all is connected with single-chip microcomputer, it also comprises digital frequency synthesizer, be DDS, the input end of described digital frequency synthesizer is connected with single-chip microcomputer, output terminal be connected with the input end of door.The model of single-chip microcomputer employing is AT89S52 in this example.
Principle of work of the present utility model is: at first, single-chip microcomputer receives the signal input and judges the swept-frequency signal frequency, single-chip microcomputer is according to the size of the output frequency of the size control DDS of signal frequency then, the output frequency that finally reaches DDS in swept-frequency signal frequency sweep process can follow the swept-frequency signal frequency to do the frequency sweep action, make count pulse that signal under each frequency all has a correspondence with it with, like this by this corresponding relation of control, make the relation of the direct reacting phase potential difference of count value of counter, its concrete steps are as follows:
Step (1): single-chip microcomputer reads swept-frequency signal, and judges the frequency value F of signal;
Step (2): single-chip microcomputer according to the frequency value F 1 of swept-frequency signal frequency value F count signal is: F1=A * F, and wherein A is a quality coefficient, its value is a constant value of setting;
Step (3): will not export phase detector to, and obtain phase signal through the swept-frequency signal of circuit-under-test network and the swept-frequency signal of process circuit-under-test network;
Step (4): with the phase signal of phase detector output and count signal with obtain count pulse,
Step (5): export count pulse to counter, obtain the count value B of umber of pulse;
Step (6): calculate phase difference value N, wherein N=360 * B/A according to count value B.
Set in this example, A=360, promptly DDS is 360 times of swept-frequency signal frequency as the frequency of count pulse.Like this, phase differential just can directly be reflected on the count value, and a count value unit is exactly the phase differential of number of degrees.
Claims (1)
1. DIGITAL FREQUENCY characteristic tester, it comprises swept-frequency signal output, the swept-frequency signal input, two shaping amplification circuits, d type flip flop, single-chip microcomputer, phase detector, with the door sum counter, described swept-frequency signal output is connected with the first shaping amplification circuit input end, the input end of the output termination d type flip flop of described first shaping amplification circuit, described swept-frequency signal input is connected with the input end of second shaping amplification circuit, the input end of the input end of described second shaping amplification circuit and the CP of d type flip flop end and phase detector is connected, the output terminal of described phase detector be connected with the input end of door, described with output terminal be connected with counter, the output terminal sum counter of described d type flip flop all is connected with single-chip microcomputer, it is characterized in that: it also comprises digital frequency synthesizer, and the input end of described digital frequency synthesizer is connected with single-chip microcomputer, output terminal be connected with the input end of door.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010201202559U CN201607486U (en) | 2010-02-24 | 2010-02-24 | Digital frequency characteristic tester |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010201202559U CN201607486U (en) | 2010-02-24 | 2010-02-24 | Digital frequency characteristic tester |
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| CN201607486U true CN201607486U (en) | 2010-10-13 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104483556A (en) * | 2014-12-10 | 2015-04-01 | 华中师范大学 | Method and device for measuring frequency characteristics based on zero-intermediate-frequency quadratic orthogonal demodulation |
| CN104535838A (en) * | 2015-01-21 | 2015-04-22 | 长沙理工大学 | Phase-frequency characteristic detector and phase-frequency characteristic detection method |
| CN106018962A (en) * | 2016-05-23 | 2016-10-12 | 广东工业大学 | Automatic digital phase demodulation circuit and system with phase difference 0 to 2pi between signals |
| CN106680584A (en) * | 2016-11-11 | 2017-05-17 | 中国科学院长春光学精密机械与物理研究所 | All-digital portable spectrum analysis system |
| CN108037363A (en) * | 2018-01-30 | 2018-05-15 | 吉林省广播电视研究所(吉林省新闻出版广电局科技信息中心) | A kind of electronic signal phase difference measuring apparatus and method |
-
2010
- 2010-02-24 CN CN2010201202559U patent/CN201607486U/en not_active Expired - Fee Related
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104483556A (en) * | 2014-12-10 | 2015-04-01 | 华中师范大学 | Method and device for measuring frequency characteristics based on zero-intermediate-frequency quadratic orthogonal demodulation |
| CN104483556B (en) * | 2014-12-10 | 2017-04-12 | 华中师范大学 | Method and device for measuring frequency characteristics based on zero-intermediate-frequency quadratic orthogonal demodulation |
| CN104535838A (en) * | 2015-01-21 | 2015-04-22 | 长沙理工大学 | Phase-frequency characteristic detector and phase-frequency characteristic detection method |
| CN104535838B (en) * | 2015-01-21 | 2017-04-12 | 长沙理工大学 | Phase-frequency characteristic detector and phase-frequency characteristic detection method |
| CN106018962A (en) * | 2016-05-23 | 2016-10-12 | 广东工业大学 | Automatic digital phase demodulation circuit and system with phase difference 0 to 2pi between signals |
| CN106018962B (en) * | 2016-05-23 | 2017-06-30 | 广东工业大学 | Phase difference is the automatic digital phase discriminator and system of 0 to 2 π between a kind of signal |
| CN106680584A (en) * | 2016-11-11 | 2017-05-17 | 中国科学院长春光学精密机械与物理研究所 | All-digital portable spectrum analysis system |
| CN108037363A (en) * | 2018-01-30 | 2018-05-15 | 吉林省广播电视研究所(吉林省新闻出版广电局科技信息中心) | A kind of electronic signal phase difference measuring apparatus and method |
| CN108037363B (en) * | 2018-01-30 | 2023-08-01 | 吉林省广播电视研究所(吉林省新闻出版广电局科技信息中心) | Device and method for measuring phase difference of electronic signals |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20101013 Termination date: 20130224 |