CN213337807U

CN213337807U - Digital frequency meter and electronic equipment

Info

Publication number: CN213337807U
Application number: CN202022489236.XU
Authority: CN
Inventors: 欧小东
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-11-02
Filing date: 2020-11-02
Publication date: 2021-06-01
Anticipated expiration: 2030-11-02

Abstract

The utility model discloses a digital frequency meter, including oscillation and frequency division module, signal processing module, gate module, counter module, latch module and decoding display module. The signal to be measured is amplified, shaped and converted by the signal processing module to generate a pulse signal to be measured and input into the gate module. The oscillation and frequency division module generates a gate control signal and a first latching signal, the gate control signal enters the gate module to control the opening/closing of the gate, and when the gate is opened, the detected pulse signal enters the counter module to count; when the gate is closed, the counter module keeps counting and outputs counting data, and the counting data is latched and displayed sequentially through the latch module and the decoding display module. The long-term latch module generates a second latch signal, the first latch signal and the second latch signal are combined to control the time interval of the latch module for latching the counting data, and the data refreshing time interval can be flexibly controlled.

Description

Digital frequency meter and electronic equipment

Technical Field

The utility model relates to an electronic measurement technical field, concretely relates to digital frequency meter and electronic equipment.

Background

The digital frequency meter is a digital instrument for measuring and displaying the number of pulses in unit time, and the working principle is as follows: when the number of the measured pulse signals measured in the specific time T is N, the frequency f of the measured pulse signals is N/T. The digital frequency meter is a typical practical training case in digital circuit teaching, in the existing digital frequency meter design circuit, the data refreshing time interval controlled by a latch is short and fixed, and students can not read frequency data easily, which may cause recording errors; the existing digital frequency meter design circuit has the problem of lack of a self-checking circuit, so that students can read frequency data but cannot judge whether the read data is correct; in addition, the frequency measurement range of the existing digital frequency meter design circuit is fixed and not expandable, and the design flexibility is poor.

SUMMERY OF THE UTILITY MODEL

To the defect among the prior art, the utility model provides a digital frequency meter, its aim at makes data refresh time interval steerable.

In a first aspect, a digital frequency meter includes an oscillation and frequency division module, a signal processing module, a gate module, a counter module, a latch module, and a decoding display module. The signal to be measured is amplified, shaped and converted by the signal processing module to generate a pulse signal to be measured and input into the gate module. The oscillation and frequency division module generates a gate control signal and a first latching signal, the gate control signal enters the gate module to control the opening/closing of the gate, and when the gate is opened, the detected pulse signal enters the counter module to count; when the gate is closed, the counter module keeps counting and outputs counting data, and the counting data is latched and displayed sequentially through the latch module and the decoding display module. The long-term latch module generates a second latch signal, the first latch signal and the second latch signal are combined to control the time interval of the latch module for latching the counting data, and the data refreshing time interval can be flexibly controlled.

Preferably, the long-term latch module comprises a long-term latch switch, one end of the long-term latch switch is connected with the high level, and the other end of the long-term latch switch is connected with the input end of the latch module.

Preferably, the long-term latch module further includes an isolation module, the isolation module includes a first isolation diode, a first isolation resistor and a second isolation diode, two ends of the first isolation resistor are respectively connected to a negative electrode of the first isolation diode and a negative electrode of the second isolation diode, a positive electrode of the first isolation diode is connected to the oscillation and frequency division module, and a positive electrode of the second isolation diode is connected to the long-term latch switch. The first isolation diode, the first isolation resistor and the second isolation diode are used for isolating mutual influence between the first latching signal and the second latching signal.

Preferably, the long-term latch module further comprises a defibrillation module, the defibrillation module comprises a defibrillation capacitor, one end of the defibrillation capacitor is connected with the first isolation resistor, and the other end of the defibrillation capacitor is grounded. Anti-chatter capacitor C₃For preventing "jitter" in the closing/opening instants of the long-term latch switch from causing the latch module to false trigger.

Preferably, the system further comprises a self-checking/checked signal control module, wherein the input end of the self-checking/checked signal control module is respectively connected with the input end of the checked signal and the input end of the oscillation and frequency division module, the output end of the self-checking/checked signal control module is connected with the input end of the signal processing module, and students can perform equipment self-checking through self-checking signals and perform frequency measurement experiments after confirming that the digital frequency meter works normally.

Preferably, the system comprises a spread spectrum module, wherein the input end of the spread spectrum module is connected with the output end of the signal processing module, the output end of the spread spectrum module is connected with the input end of the gate module, and the spread spectrum module enables the measurement range of the digital frequency meter to be expanded, so that the flexibility is improved.

Preferably, the gate module generates a reset signal, and the reset signal triggers the reset terminal of the counter module to be cleared.

Preferably, the decoding display module comprises a current-limiting resistor and L displays, wherein L is more than or equal to 2, the L display modules are connected in parallel and then connected in series with the current-limiting resistor, and the L displays share 1 current-limiting resistor, so that the size of the digital frequency meter is reduced, and the uniformity of the light-emitting brightness of the displays is ensured.

Preferably, the oscillation and frequency division module comprises an oscillation and fourteen-level frequency divider module and a quartering frequency divider module, and an output end of the oscillation and fourteen-level frequency divider module is connected with an input end of the quartering frequency divider module; the oscillation and fourteen-level frequency divider module generates a self-detection signal and a first reset control signal, and the self-detection signal is input to the self-detection/detected signal control module; the four-frequency divider module generates a gate control signal and a second reset control signal, and the gate control signal enters the gate module to control the opening/closing of the gate; the first reset control signal and the second reset control signal are combined to enter the gate module and generate a reset signal.

In a second aspect, an electronic device comprises the digital frequency meter of the first aspect.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the technical solutions in the prior art will be briefly described below. Throughout the drawings, like elements or portions are generally identified by like reference numerals. In the drawings, elements or portions are not necessarily drawn to scale.

Fig. 1 is a block diagram of an embodiment of the present invention;

fig. 2 is a detailed block diagram of an embodiment of the present invention;

fig. 3 is a schematic circuit diagram according to an embodiment of the present invention.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and therefore are only examples, and the protection scope of the present invention is not limited thereby.

It is to be noted that unless otherwise specified, technical or scientific terms used herein shall have the ordinary meaning as understood by those skilled in the art to which the present invention belongs.

As shown in fig. 1 and fig. 2, the present embodiment provides a digital frequency meter, which includes an oscillation and frequency division module, a signal processing module, a gate module, a counter module, a latch module, and a decoding and displaying module; the oscillation and frequency division module comprises an oscillation and fourteen-level frequency divider and a quartered frequency divider, the signal processing module comprises an amplification module and a waveform shaping and conversion module, the gate module comprises a gate and a counter reset signal generation circuit, the counter module comprises 100-system counters 1-3 and carry pulse generation modules 1-2, the latch module comprises latches 1-3, and the decoding display module comprises decoding displays 1-3. The signal to be measured is input from the input end of the signal to be measured, amplified, shaped and converted by the signal processing module to generate a pulse signal to be measured, and the pulse signal is input to the gate and counter reset signal generating circuit. After oscillation is connected in series with the fourteen-level frequency divider and the quarternary frequency divider, a gate control signal and a first latch signal are generated, and the gate control signal enters a gate and counter reset signal generation circuit to control the opening/closing of the gate; when the gate is opened, the pulse signal to be tested enters the 100-system counter 1 for counting, the carry clock generating circuit 1 receives the feedback data of the 100-system counter 1 and triggers the 100-system counter 2 to count, and similarly, the carry clock generating circuit 2 receives the feedback data of the 100-system counter 2 and triggers the 100-system counter 3 to count; when the gate is closed, the 100 system counters 1-3 count and hold and output count data, and the count data sequentially passes through the latches 1-3 and the decoding displays 1-3 to be latched and displayed. The digital frequency meter also comprises a long-term latch module, the long-term latch module generates a second latch signal, the first latch signal and the second latch signal are combined to control the time interval of the latch module for latching counting data, the data refreshing time interval can be flexibly controlled, and reading and recording of students are facilitated.

As shown in FIG. 3, the long-term latch module includes a long-term latch switch S₃Latching switch S for a long time₃Is connected to the high level and the other end is connected to the latch module. The long-term latch module also comprises an isolation module which comprises a diode VD₅Resistance R₆And a diode VD₆Resistance R₆Are respectively connected with a diode VD₅Cathode of (2), diode VD₆Is connected to the cathode of a diode VD₅The anode of the diode is connected with the oscillation and frequency division module, and the diode VD₆Positive pole and latch switch S₂And (4) connecting. Diode VD₅Resistance R₆And a diode VD₆For isolating the first latch signal and the second latch signal from each other. The long-term latch module also comprises a defibrillation module which comprises a defibrillation capacitor C₃Capacitor C for eliminating vibration₃One end of (A)And a resistor R₆And the other end is grounded. Anti-chatter capacitor C₃For preventing "jitter" in the closing/opening instants of the long-term latch switch from causing the latch module to false trigger.

The digital frequency meter also comprises a self-checking/detected signal control module which comprises a single-pole double-throw switch S₁Single-pole double-throw switch S₁The movable contact is connected with the amplifying module, the first static contact is connected with the input end of the tested signal, and the second static contact is connected with the input end of the self-checking signal. When the second stationary contact is connected with the self-checking signal input end, the student can perform equipment self-checking through the self-checking signal, and then perform a frequency measurement experiment after confirming that the digital frequency meter works normally. Wherein, the single-pole double-throw switch is simple and easy to use, and is convenient for students to operate.

The digital frequency meter also comprises a spread spectrum module, wherein the input end of the spread spectrum module is connected with the output end of the signal processing module, the output end of the spread spectrum module is connected with the input end of the gate module, the spread spectrum module comprises N ten-frequency divider chips 74HC160, and N is a natural number. The digital frequency meter also comprises a range selection switch S₂Range selection switch S₂Is a single-pole double-throw switch, a range selection switch S₂The movable contact of the gate module is connected with the input end of the gate module, the first fixed contact is connected with the input end of the signal processing module, and the second input end of the gate module is connected with the input end of the spread spectrum module. In this embodiment, the spectrum spreading module includes 1 74HC160 chip and equivalent range selection switch S₂When the digital frequency meter is connected with the signal processing module, the measurement range of the digital frequency meter is 1-999999 Hz, and the measurement error is 1 Hz; equivalent range selection switch S₂When the frequency meter is connected with the spread spectrum module, the measurement range of the digital frequency meter is 10-9999990 Hz, and the measurement error is 10 Hz. In other embodiments, the spreading module may include multiple 74HC160 chips, and the use of the spreading module increases design flexibility.

The gate module also generates a reset signal, and the reset signal triggers the reset end of the counter module to be reset. The decoding display module comprises a current-limiting resistor and L displays, wherein L is more than or equal to 2, the L display modules are connected in parallel and then connected in series with the current-limiting resistor, and the L displays share 1 current-limiting resistor, so that the size of the digital frequency meter is reduced, and the uniformity of the light emitting brightness of the displays is ensured.

The oscillation and frequency division module comprises an oscillation and fourteen-level frequency divider module and a four-frequency divider module, and the output end of the oscillation and fourteen-level frequency divider module is connected with the input end of the four-frequency divider module. The oscillation and fourteen-level frequency divider module generates a self-detection signal and a first reset control signal, and the self-detection signal is input to the self-detection/detected signal control module. The four-frequency divider module generates a gate control signal and a second reset control signal, the gate control signal enters the gate module to control the opening/closing of the gate, and the first reset control signal and the second reset control signal are combined to enter the gate module and generate a reset signal.

Based on the same inventive concept, the embodiment of the present invention further provides an electronic device, which includes the above digital frequency meter.

The utility model is provided with a long-term latch switch, which can flexibly control the interval of data refreshing time and is convenient for students to record data; the design of the self-checking/detected signal control module enables students to carry out equipment self-checking through the self-checking signal; the utility model discloses still be equipped with the spread spectrum module, frequency measurement range is expanded, has improved the flexibility. The utility model discloses well display module current-limiting resistor of sharing has not only reduced the volume of digital frequency meter, has still ensured the unity of display luminous luminance.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the scope of the embodiments of the present invention, and are intended to be covered by the claims and the specification.

Claims

1. A digital frequency meter comprises an oscillation and frequency division module, a signal processing module, a gate module, a counter module, a latch module and a decoding display module; the measured signal is amplified, shaped and converted by the signal processing module to generate a measured pulse signal and the measured pulse signal is input to the gate module; the oscillation and frequency division module generates a gate control signal and a first latching signal, and the gate control signal enters the gate module to control the opening/closing of the gate; when the gate is opened, the pulse signal to be detected enters a counter module for counting; when the gate is closed, the counter module keeps counting and outputs counting data, and the counting data is latched and displayed sequentially through the latch module and the decoding display module; the method is characterized in that: the long-term latch module is used for generating a second latch signal, and the first latch signal and the second latch signal are combined to control the latch time interval of the latch module for latching the counting data.

2. A digital frequency meter according to claim 1, wherein: the long-term latch module comprises a long-term latch switch, one end of the long-term latch switch is connected with the high level, and the other end of the long-term latch switch is connected with the input end of the latch module.

3. A digital frequency meter according to claim 2, wherein: the long-term latch module further comprises an isolation module, the isolation module comprises a first isolation diode, a first isolation resistor and a second isolation diode, two ends of the first isolation resistor are respectively connected with the negative electrode of the first isolation diode and the negative electrode of the second isolation diode, the positive electrode of the first isolation diode is connected with the oscillation and frequency division module, and the positive electrode of the second isolation diode is connected with the long-term latch switch.

4. A digital frequency meter according to claim 3, wherein: the long-term latch module further comprises a defibrillation module, the defibrillation module comprises a defibrillation capacitor, one end of the defibrillation capacitor is connected with the first isolation resistor, and the other end of the defibrillation capacitor is grounded.

5. A digital frequency meter according to claim 1, wherein: the system also comprises a self-checking/detected signal control module, wherein the input end of the self-checking/detected signal control module is respectively connected with the input end of the detected signal and the input end of the oscillation and frequency division module, and the output end of the self-checking/detected signal control module is connected with the input end of the signal processing module.

6. A digital frequency meter according to claim 4, wherein: the system also comprises a spread spectrum module, wherein the input end of the spread spectrum module is connected with the output end of the signal processing module, and the output end of the spread spectrum module is connected with the input end of the gate module.

7. A digital frequency meter according to claim 6, wherein: the gate module generates a reset signal, and the reset signal triggers the reset end of the counter module to be reset.

8. A digital frequency meter according to claim 7, wherein: the decoding display module comprises a current-limiting resistor and L displays, wherein L is more than or equal to 2, and the L displays are connected in parallel and then connected in series with the current-limiting resistor.

9. A digital frequency meter according to claim 8, wherein: the oscillation and frequency division module comprises an oscillation and fourteen-level frequency divider module and a fourteen-level frequency divider module, and the output end of the oscillation and fourteen-level frequency divider module is connected with the input end of the fourteen-level frequency divider module; the oscillation and fourteen-level frequency divider module generates a self-detection signal and a first reset control signal, and the self-detection signal is input to the self-detection/detected signal control module; the four-frequency divider module generates a gate control signal and a second reset control signal, and the gate control signal enters the gate module to control the opening/closing of a gate; the first reset control signal and the second reset control signal are combined to enter the gate module and generate a reset signal.

10. An electronic device, characterized in that it comprises a digital frequency meter according to any one of claims 1-9.