CN88219577U

CN88219577U - Ultralow frequency signal generator

Info

Publication number: CN88219577U
Application number: CN 88219577
Authority: CN
Inventors: 张利国; 贾振欧
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-05-11
Filing date: 1988-05-11
Publication date: 1988-11-09

Abstract

The utility model discloses an ultralow frequency signal generator which can generate ultra low frequency electrical signals with cycles of 1 second to 3600 seconds, used for self-recording instruments such as an electronic potentiometer to do performance test, and composed of a clock pulse generator, a reversible counter, a logical gating circuit, a bistable trigger and a D/A convertor. The taken method that clock pulse signals are input to the reversible counter for reversible counting, and converted into low frequency electrical signals by the D/A convertor solves the defect existing in the prior art. The utility model has the advantages of simple structure, low cost, high precision, reliable work, etc., suitable for metering testing departments as an ultra low frequency standard signal source.

Description

Ultralow frequency signal generator

The utility model discloses a kind of Signal Generator of Ultra-low Frequency, the cycle that can produce is used for the operation test to graphic instruments such as electron potentiometers greater than 1 second the ultralow frequency signal of telecommunication, is a kind of electric measuring instrument.

At present, the domestic Signal Generator of Ultra-low Frequency that is suitable for such use, only have with the motor drives slide wire resistor and do uniform rotation and produce the experiment type product of ultralow frequency periodic electric signal, an index such as its precision and life-span is all poor, can not satisfy the requirement of national metrological verification regulations fully.In addition, common Signal Generator of Ultra-low Frequency in the electronics industry approved product, product as models such as XD8 type, XD5 type, XFD-8A, its structural principle is by the Schmidt trigger shaping with the external trigger signal of some cycles, become the square wave that pulse duration is a half period, become triangular wave through integrator again.Can also become sine wave by shaping network in addition.The signal time error that this quasi-instrument is exported is generally 2%, and accuracy of waveform is generally 1%.The synthesis precision of this Signal Generator of Ultra-low Frequency is better, but complex structure, fetch long price is unsuitable for general middle-size and small-size Measurement Laboratory specialized configuration.The defective that above-mentioned existing procucts exist separately is that design of the present utility model has proposed tasks clear.

Invention task of the present utility model provides a kind of simple structure, precision height, good reliability, the Signal Generator of Ultra-low Frequency that cost is low.

Figure of description 1 is the electric functional-block diagram of structure of the present utility model.

Figure of description 2 is sprocket pulse generator or door, NAND gate and flip and flop generator electrical schematic diagrams of the utility model embodiment.Among the figure: 1 sprocket pulse generator, 2 OR circuit, 3 NAND gate circuit, 4 flip and flop generators.

Figure of description 3 is up/down binary counter and D/A converter electrical schematic diagrams of the utility model embodiment.Among the figure: 5 up/down binary counters, 6D/A transducer.

Technical essential of the present utility model is that the sprocket pulse signal input up/down binary counter of certain frequency that a sprocket pulse generator is sent is counted, when every meter is expired half period, the control gate circuit sending signal makes the forward-backward counter counter-rotating by flip and flop generator, thereby produce a periodically variable digital quantity of intercropping at any time on request, be transformed into corresponding analog electrical signal through D/A converter again and use for output.

Now, the utility model is specified according to Figure of description.Signal Generator of Ultra-low Frequency comprises that sprocket pulse generator 1, OR circuit 2, NAND gate circuit 3, flip and flop generator 4, up/down binary counter 5 and D/A converter 6 and power unit constitute.The sprocket pulse generator is by IC ₁, IC ₂, K ₁And quartz crystal and resistance capacitance composition.C ₁, C ₂Form π type feedback network, IC with quartz crystal L ₁Be the frequency divider of band oscillator, K ₁Be the sprocket pulse frequency selective switch.IC ₂Be inverter buffer, as IC ₁And IC ₃Between interface circuit; OR circuit is by IC ₈, IC ₉And 1/2IC ₇Form.IC ₈, IC ₉For two 3 input NOR gate, with 1/2IC ₇ Common formation 12 inputs or door; NAND gate circuit is by 1/2IC ₇Form IC ₇Be two 4 input nand gates; Flip and flop generator is by BG ₁₃With BG ₁₄And D ₁D ₂Form; Up/down binary counter is by three tetrad forward-backward counters (doubleclocking) IC ₄, IC ₅, IC ₆Series connection constitutes 12 up/down binary counters mutually, utilizes IC ₃32 input nand gates change it into single clock input.K ₂Be run switch, K ₄Be reset switch; D/A converter is 12 D/A converters, discloses one in the Figure of description by BG ₁～BG ₁₂And resistance R ₈～R ₁₉12 D/A converters of the discrete component that constitutes are intended to reduce cost of the present utility model, use integrated circuit such as AD7521 that circuit is simplified reliably more undoubtedly.K ₃Adjust switch for output amplitude, adjust W ₁Can determine the upper limit current potential of output signal, W ₂Be used for adjusting the potential minimum scope of output waveform.

The utility model is work like this: the pulse signal of the certain frequency that the sprocket pulse generator sends is sent into the up/down binary counter counting, adopted two logic gates to be connected with counter, gate circuit is directly controlled flip and flop generator, adding up or the tired conversion that subtracts counting by the flip and flop generator control counter again, add up when finishing the half period respectively at some cycle inside counting devices, half period tires out when subtracting counting, then can obtain the triangular waveform signal of telecommunication of one-period variation at the D/A converter output.Nature adds that shaping network also can become it sine wave and wait other waveforms, and this is known to those of ordinary skill in fact.

Here it is to be noted IC ₂, IC ₃Setting only be owing to the different corresponding compensatory approaches that adopt of the type of selecting integrated circuit for use, be not the indispensable part in the utility model formation.In addition, the structure of D/A converter also can adopt 12 D/A converters of integrated circuit to connect operation amplifier circuit to constitute fully.

In sum, the utility model has the advantage that simple structure is reliable, cost is low really, and its synthesis precision reaches ± and 0.05%, be a kind of more satisfactory electric measuring instrument.

Below elaborate by 2,3 couples of embodiment of Figure of description, in the hope of further openly the utility model.IC among the embodiment ₁Adopted 14 grades of frequency dividers of CC4060 band oscillator, directly drawn 2H by 3 pin, 1 pin ₂, 8H ₂Sprocket pulse.IC ₂Adopt CC4049 six inverter buffers 1/6 as interface circuit, to solve IC ₁, IC ₃Level requires inconsistent problem.IC ₃3/4 of 74LSOO 42 input nand gates have been adopted.IC ₄, IC ₅, IC ₆Three 74LS193 tetrad forward-backward counters have been adopted.IC ₇Be two 4 input nand gates of 74LS20.IC ₈, IC ₉Be 2/3 of 74L,S27 33 input NOR gate.BG ₁～BG ₁₄Adopted the 3DK7 silicon switching triode, D ₁D ₂Be 2AP15 rectifier diode, W ₁5 Ω wirewound potential meters, W ₂100 Ω potentiometers, R ₈～R ₁₉Be one group of resistance that the resistance Geometric Sequence is arranged, its common ratio is 2, high accuracy high stability resistance such as available metal film.The selection of other resistance, capacitor is known the those skilled in the art, list no longer one by one, present embodiment can produce 1 the week/hour, 4 the week/hour triangular signal.

Claims

1, a kind ofly is used for electrometric Signal Generator of Ultra-low Frequency, comprises power unit, it is characterized in that being constituted by sprocket pulse generator 1, OR circuit 2, NAND gate circuit 3, flip and flop generator 4, up/down binary counter 5 and D/A converter 6.

2,, it is characterized in that sprocket pulse generator 1 is by IC according to the described Signal Generator of Ultra-low Frequency of claim 1 ₁, IC ₂, K ₁And quartz crystal and resistance capacitance composition, IC ₁14 grades of frequency dividers of CC4060 band oscillator have been adopted, IC ₂Be inverter buffer, can adopt 1/6CC4049.

3,, it is characterized in that OR circuit 2 is by IC according to the described Signal Generator of Ultra-low Frequency of claim 1 ₈, IC ₉And 1/2IC ₇Form IC ₈, IC ₉For two 3 input NOR gate, with 1/2IC ₇Form 12 inputs or door, IC ₈, IC ₉Be 2/3 of 74L,S27 33 input NOR gate, IC ₇Be two 4 input nand gates of 74LS20.

4,, it is characterized in that NAND gate circuit is by 1/2IC according to the described Signal Generator of Ultra-low Frequency of claim 1 ₇Form IC ₇Be two 4 input nand gates.

5,, it is characterized in that flip and flop generator 4 is by BG according to the described Signal Generator of Ultra-low Frequency of claim 1 ₁₃With BG ₁₄And D ₁D ₂Form BG ₁₃, BG ₁₄Adopted 3DK ₇Silicon switching triode, D ₁, D ₂Be the 2AP15 rectifier diode.

6,, it is characterized in that up/down binary counter 5 is by 3 tetrad forward-backward counter IC according to the described Signal Generator of Ultra-low Frequency of claim 1 ₄, IC ₅, IC ₆Series connection constitutes 12 up/down binary counters, IC mutually ₄, IC ₅, IC ₆Three 74LS193 have been adopted.

7,, it is characterized in that D/A converter 6 is 12 D/A converters according to the described Signal Generator of Ultra-low Frequency of claim 1.