CN210514493U - Intelligent miniature portable sweep generator - Google Patents

Abstract

The utility model discloses a miniature portable sweep-frequency instrument of intelligence, including microcontroller, DDS module and button module, button module's signal output part with microcontroller's signal input part connects, the DDS module with communication connection between the microcontroller. The utility model provides a sweep-frequency instrument passes through microcontroller and DDS module and realizes the frequency sweep, has not only improved function generator's stability, has reduced manufacturing cost, but also has frequency conversion fast and resolution ratio characteristics such as high. The key module realizes man-machine exchange, can realize selection of a frequency sweeping mode, and realizes selection of a proper frequency signal for humanization or adoption of an automatic frequency sweeping mode.

Description

Intelligent miniature portable sweep generator

Technical Field

The utility model relates to a sweep-frequency instrument especially relates to a miniature portable sweep-frequency instrument of intelligence.

Background

In recent years, the development of the electronic industry is rapid, the low-frequency scanner has irreplaceable use in electronic technology experiments and equipment detection, most of the low-frequency scanners used in advanced schools at present are 5MHZ, for some experiments, a better signal source cannot be provided, a lot of inconvenience is generated in experimental operation, and the frequency scanner with multiple frequency bands is very expensive, complex in structure and high in power consumption.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problem that current sweep generator exists, the utility model aims at providing a stability is good, low in manufacturing cost, but also has the miniature portable sweep generator of intelligence of characteristics such as frequency conversion is fast, resolution ratio is high and the controllability is strong.

For realizing the utility model discloses a purpose, the miniature portable frequency scanner of intelligence that provides here, including microcontroller, DDS module and button module, button module's signal output part with microcontroller's signal input part connects, the DDS module with communication connection between the microcontroller.

In order to make the sinusoidal signal distortion factor of DDS module output little, the utility model provides a sweep generator still including connect in DDS module signal output part's signal conditioning module. The signal adjusting module adjusts the sinusoidal signal output by the DDS module, so that the stability of the sinusoidal signal output by the DDS module is ensured.

In some embodiments, the frequency scanner of the present invention further comprises a frequency display module connected to the signal output terminal of the microcontroller. And displaying the current frequency through a frequency display module.

The utility model has the advantages that: the utility model provides a sweep-frequency instrument passes through microcontroller and DDS module and realizes the frequency sweep, has not only improved function generator's stability, has reduced manufacturing cost, but also has frequency conversion fast and resolution ratio characteristics such as high. The key module realizes man-machine exchange, can realize selection of a frequency sweeping mode, and realizes selection of a proper frequency signal for humanization or adoption of an automatic frequency sweeping mode.

Drawings

Fig. 1 is a schematic block diagram of a frequency scanner provided by the present invention;

fig. 2 is a schematic circuit diagram of the frequency scanner provided by the present invention.

Detailed Description

The claimed embodiments of the invention are described in further detail herein with reference to the accompanying drawings and the detailed description.

The utility model discloses a claimed technical scheme is a miniature portable frequency scanner of intelligence, and its principle is as shown in fig. 1 and 2, included the microcontroller that is used for data processing and output control signal, be used for according to the sinusoidal DDS module of control signal output of microcontroller output and be used for mode selection and frequency plus-minus button module, button module's signal output part is connected with microcontroller's signal input part, communication connection between DDS module and the microcontroller.

The key module is used for selecting the working mode of the sweep frequency instrument to be an automatic frequency sweeping mode or a manual frequency modulation mode, and when the working mode is in the manual frequency modulation mode, the frequency can be increased or decreased through the key module. The method comprises the following steps that 3 independent keys are adopted to form a key module, one key is pressed to enter an automatic frequency sweeping mode, and an automatic frequency sweeping range is set according to conditions, such as 1 MHZ-40 MHZ; the other two keys are in a manual frequency modulation mode, and the manual frequency modulation mode can realize a step adjustment function, and the two keys are respectively used for realizing the functions of frequency addition and frequency reduction, namely the increase or reduction of any frequency can be realized in a frequency modulation range; if 1MHz stepping is adopted, namely adding key or subtracting the key frequency by 1MHz or subtracting 1MHz by manually pressing.

Here, the utility model provides a sweep-frequency instrument is still including connecting in the sinusoidal signal to DDS module output of DDS module signal output part and taking care of the signal conditioning module. The utility model discloses the signal conditioning module that adopts here has included voltage follower and filter circuit, and the voltage follower adopts and is shared the collector circuit to constitute, specifically includes triode T, and triode T's base connects the signal output part of DDS module through electric capacity Cb1, and the projecting pole is through resistance Re ground connection, and the collecting electrode connects the power; a resistor Rb is connected in series between a collector and a base of the triode T, and a power supply VS and a resistor RS are connected in series between the base and an emitter; the emitter of the triode T is loaded on the filter circuit as the output end of the voltage follower through a capacitor Cb 2.

The filter circuit adopts an RC filter circuit comprising a resistor R and a capacitor C, and utilizes an RC element to realize a passive filter circuit, so that the passive filter circuit has the advantages of small size, low cost, simple circuit and the like; and the RC low-pass circuit has a transmission coefficient K which is 1 when the signal source frequency F is close to 0 and 0 when the signal source frequency F is close to infinity. Make the utility model provides a sweep-frequency instrument can pass through low frequency signal, and high frequency signal is restrained, has improved the quality of wave form through RC low pass filter circuit, improves the stability of signal source, lets output waveform enough "pure".

In addition, in order to display the sinusoidal signal output by the DDS module better and intuitively, the utility model provides a sweep generator which also comprises a frequency display module connected with the signal output end of the microcontroller; the frequency display module displays the current output frequency value by using a nixie tube, and the accuracy can be up to 1 MHZ. Of course, other display modules such as an LED, an LCD, or an external oscilloscope may be used to display the frequency value.

The utility model provides a microcontroller among the sweep generator comprises the minimum system of singlechip, and it mainly includes singlechip, three terminal voltage stabilizing circuit, reset circuit and clock circuit, and the singlechip can adopt any computer program that can save and move the computer program of saving in it behind loading voltage.

The DDS module comprises a phase accumulator, a waveform memory, a digital-to-analog converter and a low-pass filter which are connected in sequence, the DDS module mainly accumulates the rotation quantity of a sine wave through the phase accumulator to obtain phase information corresponding to an output control frequency FS, then the waveform memory converts the phase into an amplitude value of a corresponding phase, and the value is sent to the digital-to-analog converter in a binary mode; the digital-to-analog converter receives the digital signal, converts the digital signal into an analog signal and outputs the analog signal to generate an original sinusoidal signal. The DDS module is a direct digital frequency synthesizer, and an AD9851 chip is adopted as the DDS module.

The DDS module signal generation principle is that an AD9851 chip is adopted to averagely divide 360 degrees into 2^ N equal parts, and each equal part corresponds to a phase point in the range of 0 to 360 degrees in a sine wave; assume that the input clock is F0 and the output frequency is FS. Each rotation through an angle of 360/2 < SP > N </SP >, a phase increment of a sine wave with a frequency of F0/2 < SP > N </SP > is generated; the required output frequency FS can be obtained from equation (1) by simply selecting the appropriate frequency control word K.

FS＝(F0×K)/2^N (1)

After passing through the phase accumulator, phase information corresponding to the output control frequency FS is obtained, then the waveform memory converts the phase into an amplitude value of the corresponding phase, and the value is sent to the digital-to-analog converter in a binary form. The digital-to-analog converter receives the digital signal, converts the digital signal into an analog signal and outputs the analog signal. The RC filter circuit and the voltage follower are utilized to ensure that the output waveform is not distorted and the effect consistent with the actual requirement is achieved.

In order to guarantee the portability of whole sweep-frequency instrument, the utility model provides a sweep-frequency instrument still includes power module, and power module provides for entire system and closes 5V's operating voltage, can adopt lithium cell, button cell, perhaps adopts power conversion circuit to convert the commercial power into 5V voltage.

The utility model provides a use of sweep-frequency instrument is: and (3) electrifying, wherein the test process is divided into two parts, namely 1, self-scanning function test of the sweep generator. 2 step frequency test of a sweep generator. And after the automatic scanning key is pressed, the frequency is added with 1MHZ cyclic change once per 1 second period, and the test result is consistent with the design requirement. And finally, testing the step control function, pressing down a step function key, and accurately increasing or decreasing the frequency according to the 1MHZ precision. The whole test process is compared with the oscilloscope reading through the nixie tube display frequency, and the frequency test experiment result is accurate and effective.

The sweep generator adopts the singlechip with better stability and low cost, the control signal of the singlechip is used for driving the AD9851 chip, and the voltage follower and the RC filter circuit are used, so that the distortion degree of sinusoidal signals output by the system is small, the system serving as a standard signal source can be widely applied to experiments such as electronic circuit design, analog circuits and digital circuits developed by colleges and universities, and can be applied to testing of different frequencies of the electronic circuit when working in a sweep mode.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims (9)

1. The utility model provides a miniature portable frequency scanner of intelligence which characterized in that: the DDS key comprises a microcontroller, a DDS module and a key module, wherein the signal output end of the key module is connected with the signal input end of the microcontroller, and the DDS module is in communication connection with the microcontroller.

2. An intelligent miniature portable frequency scanner as claimed in claim 1, wherein: the DDS module also comprises a signal conditioning module connected to the signal output end of the DDS module.

3. An intelligent miniature portable frequency scanner as claimed in claim 2, wherein: the signal conditioning module comprises a voltage follower and a filter circuit, and the signal output by the DDS module is output after passing through the voltage follower and the filter circuit.

4. An intelligent miniature portable frequency scanner as claimed in claim 3, wherein: the filter circuit is an RC filter circuit.

5. An intelligent miniature portable frequency scanner according to any one of claims 1 to 4, wherein: the frequency display module is connected to the signal output end of the microcontroller.

6. An intelligent miniature portable frequency scanner as claimed in claim 5, wherein: the frequency display module is a nixie tube.

7. An intelligent miniature portable frequency scanner as claimed in claim 1, wherein: the microcontroller is a minimum system of a single chip microcomputer and comprises the single chip microcomputer, a three-terminal voltage stabilizing circuit, a reset circuit and a clock circuit.

8. An intelligent miniature portable frequency scanner as claimed in claim 1, wherein: the DDS module comprises a phase accumulator, a waveform memory, a digital-to-analog converter and a low-pass filter which are connected in sequence.

9. An intelligent miniature portable frequency scanner as claimed in claim 1, wherein: the key module comprises 4 independent keys, and each key is connected between the signal input end of the microcontroller and the ground in series.

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