CN1564000A - Digital signal source with waveform indication - Google Patents

Abstract

The signal source consists of controller, waveform sampling and processing module, program controlled clock module, frequency measurement and keyboard control module and LCD module. The controller is connected to waveform sampling and processing module, program controlled clock module, frequency measurement and keyboard control module and LCD module respectively. Input signal is inputted to waveform sampling and processing module and frequency measurement module. The program controlled clock module is connected to waveform sampling and processing module. Less key button are placed on panel. Besides frequency, amplitude of signal even waveform of signal can be displayed without need of using oscilloscope.

Description

The derived digital signal that the band waveform shows

Technical field:

The present invention relates to a kind of measurement mechanism, be specifically related to a kind of derived digital signal with the waveform demonstration.

Background technology:

In automation equipment and system, often need carry out the test of performance and the transmission of information, these all be unable to do without the foundation of certain waveform as test and transmission.Waveform commonly used has sine wave, square wave, triangular wave etc., and signal source promptly is the instrument that is used to produce these waveforms.

In the engineering practice, often need signal source that frequency and amplitude can regulate ingredient, or be used as test, adjust the experimental apparatus of electronic equipment as electronic equipment.

Existing signal source equipment has the following disadvantages:

(1) button is too many on the existing signal source panel, user's operating difficulties;

(2) an existing signal source frequency indicating signal, shows signal amplitude not, signal amplitude need measure by ac millivoltmeter;

(3) the existing signal source waveform of shows signal not, the user often need come the whether distortion of observation signal waveform by oscillograph.

Summary of the invention:

Technical matters to be solved by this invention is the defective that overcomes above-mentioned prior art, provide a kind of can be on panel directly frequency indicating signal and amplitude and derived digital signal simple to operate.

Technical matters of the present invention is to realize by following technical scheme.It is characterized in that it comprises controller, waveform sampling and processing module, program control watchdog timer module, frequency measurement and Keyboard Control module and LCD MODULE, described controller links to each other with Keyboard Control module and LCD MODULE with processing module, program control watchdog timer module, frequency measurement with waveform sampling respectively, input signal is sent in waveform sampling and processing module and the frequency measurement module, and program control watchdog timer module links to each other with processing module with waveform sampling simultaneously.Described controller comprises two single-chip microcomputers and impact damper, and wherein a single-chip microcomputer links to each other with peripheral circuit by impact damper, joins by serial ports and another single-chip microcomputer; Described waveform sampling and processing module comprise that static store, analog to digital converter, able to programme patrolling seize device, and described static store is seized device and linked to each other with able to programme patrolling, and analog to digital converter is then seized device and linked to each other with able to programme patrolling with static store respectively; Described watchdog timer module comprises light emitting diode, watchdog timer generator, level transferring chip and optocoupler, and wherein optocoupler and triode are formed signal isolation circuit; Described frequency measurement and Keyboard Control module are made up of two impact dampers, comparer, counter, digital to analog converter, operational amplifier and light emitting diodes, and wherein comparer links to each other with counter; Described LCD MODULE comprises liquid-crystal controller, LCD and storer, and wherein liquid-crystal controller interconnects with LCD and storer respectively.

The present invention has following technique effect:

(1) simplified panel, button is less on the panel, and is simple to operate, easy to use, is difficult for makeing mistakes;

(2) except that the frequency of shows signal, go back the amplitude of shows signal;

(3) the band waveform shows, the user needn't connect oscillograph and observe whether distortion of waveform;

(4) user can reduce the expense of buying miscellaneous equipment, cuts down expenses.

Description of drawings:

Fig. 1 is a schematic block circuit diagram of the present invention;

Fig. 2 is a controller module circuit diagram of the present invention;

Fig. 3 waveform sampling of the present invention and processing module circuit diagram;

Fig. 4 is a watchdog timer module circuit diagram of the present invention;

Fig. 5 is frequency measurement of the present invention and Keyboard Control module circuit diagram;

Fig. 6 is a LCD MODULE circuit diagram of the present invention;

Fig. 7 is system works flow process figure of the present invention;

Fig. 8 is control panel figure of the present invention.

Embodiment:

As shown in Figure 1, the present invention includes controller, waveform sampling and processing module, program control watchdog timer module, frequency measurement and Keyboard Control module and LCD MODULE, the circuit that above-mentioned each module is formed has been realized the function that the present invention will reach.Its middle controller is the present invention's a central module, link to each other with Keyboard Control module and LCD MODULE with processing module, watchdog timer module, frequency measurement with waveform sampling respectively, input signal is sent in waveform sampling and processing module and the frequency measurement module, and the watchdog timer module links to each other with processing module with waveform sampling simultaneously.

Each circuit of following division.

As shown in Figure 2, controller module of the present invention mainly adopts eight bus buffer U14 and two single-chip microcomputer U1, U17, wherein single-chip microcomputer U17 links to each other with peripheral circuit by impact damper U14, join by serial ports and another single-chip microcomputer U1, so not only can improve real-time, and make things convenient for the circuit-board laying-out wiring.U17 is general MCS51 series monolithic, and model is 89C52, mainly is responsible for the Control work of sampling, data processing and watchdog timer and liquid crystal.

The P0 mouth of single-chip microcomputer U17 and P2 mouth are mainly finished following three tasks: by eight line buffer U14 storer U15 is carried out read-write operation; Carry out interactive operation with programmable logic device (PLD) U18; The data that collect are delivered to liquid-crystal controller U11 show output.The P1 mouth is used for watchdog timer generator U21 is carried out parameter configuration, determines the frequency of the sampling clock of watchdog timer generator U21 output.

Single-chip microcomputer U1 is general MCS51 series monolithic, and model is 89C52, mainly finishes frequency measurement, DAC output and keyboard interface processing capacity, and single-chip microcomputer U1 communicates by serial ports and U17.

The P0 mouth of single-chip microcomputer U1 and P2 mouth are used for linking to each other with button on the panel, determine the order that the user will carry out.The P1 mouth is used for sending configuration words to the analog to digital converter U9 of serial line interface, determines the size of its output aanalogvoltage.The timer of single-chip microcomputer U1 is used for measuring the frequency of input signal.

U14 is an impact damper, and model is 74F245.Major function is: reception and the sending function of finishing 8 bit data bus.

Single-chip microcomputer U17 carries out exchanges data by impact damper U14 and peripheral circuit in the controller module circuit, communicates by serial ports and single-chip microcomputer U1.

As shown in Figure 3, waveform sampling of the present invention and processing module circuit comprise that static store U15, analog to digital converter U16, able to programme patrolling seize device U18, described static store U15 seizes device U18 and links to each other with able to programme patrolling, and analog to digital converter U16 then seizes device U18 and links to each other with able to programme patrolling with static store U15 respectively.

Each components and parts of following division:

D18, D19 are light emitting diode, the pilot lamp on the respective operations panel.

U15 is a static memory, and model is CY7C128A-25, and major function is that the data that collect are stored.

U16 is an analog to digital converter, and model is TLC5540, major function be will input analog signal conversion be to export after the digital signal, it is seized device U18 and links to each other with able to programme patrolling with static store U15 respectively.

U18 is a programmable logic device (PLD), and model is ISPLSI1016-E80, and major function is to finish the acquisition function of signal automatically, need not CPU and intervenes, and U15 links to each other with static store.

JP2, JP3, JP4, JP5, JP8 are jumper wire device, and major function is to finish the test function of circuit.

U19 is a three terminal regulator, and model is 7905, and major function is an output-5V supply voltage.

U8A, U8B, U8C and U8D are Sheffer stroke gate, and model is 74HC00, and major function is to negate with two TTL signals of input and after operating.

U20A, U20B, U20C, U20D, U20E and U20F are not gate, and model is: 74HC14.Major function is the TTL signal inversion with input.

The function of the circuit that U8 and U20 form is that input signal is carried out logical operation, tries to achieve control signal.

Waveform sampling and processing module mainly are made up of analog to digital converter U16, static memory U15 and the programmable logic device (PLD) U18 of 40MSPS.Produce the address by programmable logic device (PLD) U18, control analog to digital converter U16 samples, and writes static memory U15 with program control frequency.After 256 of the disposable samplings, the control of static memory U15 is handed to single-chip microcomputer U17, read by single-chip microcomputer U17 and handle the brilliant demonstration of liquor charging.Its specific operation process is: treated input signal is delivered to the analog port of analog to digital converter U16, seize the sample frequency that device U18 provides and finish sampling work according to able to programme patrolling, the data storage that collects is in static memory U15, and the address of static memory U15 is seized device U18 and provided by able to programme patrolling.After adopting full data, able to programme patrolling seized device U18 and stopped collecting work to simulating signal.

Its switching rate scope of analog to digital converter U16 of the present invention is 5 to 40MSPS, and analog bandwidth is 80MHz.Because its low side sampling rate is restricted, therefore adopt the mode of control RAM writing speed to control sampling rate.The waveform that makes reproduction for departure as far as possible accurately, actual 1 in the range of signal of 40MHz point of phase sampling weekly, phase 2 points of sampling reappear waveform weekly in 40 to 80MHz range of signal.

As shown in Figure 4, watchdog timer circuit of the present invention comprises light emitting diode D20, watchdog timer generator U21, level transferring chip U22 and optocoupler U26, U27, U28, and wherein optocoupler U26, U27, U28 and triode Q1, Q2, Q3 form signal isolation circuit.

Each components and parts of following division:

D20 is a light emitting diode, the pilot lamp on the respective operations panel.

U21 is the watchdog timer generator, and model is SY89429V, and major function is to provide sampling clock to the AD conversion chip.

U22 is a level transferring chip, and model is SY100ETL23L, and major function is that the conversion of signals that watchdog timer generator U21 is exported is a Transistor-Transistor Logic level.

JP6, JP7 are jumper wire device, and major function is to finish the test function of circuit.

U23 is a Switching Power Supply, and model is LT1086CM-3.3, and major function is an output 3.3V supply voltage.

U26, U27, U28 are optocoupler, and model is: 6N137, major function is that input and output signal is isolated.

Q1, Q2, Q3 are the positive-negative-positive triode, and model is 9012, and major function is the electric current amplification, and it and optocoupler U26, U27, U28 form signal isolation circuit.

The major function of the circuit that U26, U27, U28, Q1, Q2, Q3 form is to deliver to watchdog timer generator U21 place after input signal is isolated.

U24A, U24B, U24C, U24D, U24E, U24F are not gate, model is: LCX14, major function is that the Transistor-Transistor Logic level of input is negated, and the major function of U24A, U24B, U24C, U24D, U24E, U24F built-up circuit is to finish the logical operation of input signal.

U25A, U25B, U25C, U25D, U25E, U25F are not gate, and model is: LCX14, and major function is that the Transistor-Transistor Logic level of input is negated, the major function of U25C, U25D, U25E, U25F built-up circuit is to finish the logical operation of input signal.

The watchdog timer circuit is the key that native system is realized equivalent sampling, adopts watchdog timer generator U21 to realize.Watchdog timer generator U21 is a kind of programmable frequency compositor, and its output clock ranges is 25MHz～400MHz, step value 0.125MHz～1MHz.Watchdog timer generator U21 adopts the output of difference PECL level, and the high frequency phase locked loop realization of inner employing is very sensitive to disturbing, and therefore adopts following method to guarantee its working stability.Because watchdog timer generator U21 operating voltage range broad, this partial circuit adopt 3.3V to power separately; Single-point is connected to the power supply access point after when making sheet this partial circuit being covered copper ground connection, and forming fine wiring, the used crystal oscillator earthing of casing; Select surface mount elements for use as far as possible; Use 10uF tantalum electric capacity, 0.1uF and 0.01uF ceramic disc capacitor to each power pin filtering on request, and distinguish digital power and analog power; The serial line interface of watchdog timer generator U21 and controller is isolated with optocoupler U26, U27, U28.

The principle of work of watchdog timer module is: the control word that single-chip microcomputer U17 will write is delivered to watchdog timer generator U21 place by optocoupler U26, U27, U28 after isolating, obtain corresponding AD inversion frequency, deliver to the CLOCK IN pin of analog to digital converter U16 again by watchdog timer generator U21.

Because the frequency range of watchdog timer generator U21 output is limited, therefore need add frequency dividing circuit, with the low frequency part expansion, this function realizes with the programmable logic device (PLD) U18 of LATTICE company.CPLD offers analog to digital converter U16 as frequency of operation on the one hand with the program control two divided-frequency of frequency elder generation of watchdog timer generator U21 output, and program control more on the other hand two or five decimation-in-frequencies are controlled the RAM writing speed.

As shown in Figure 5, frequency measurement of the present invention and Keyboard Control modular circuit be by two impact damper U2, U3, comparer U4, and counter U5, digital to analog converter U9, operational amplifier U10 and light emitting diode D1～D16 forms, and wherein comparer U4 links to each other with counter U5.

Each components and parts of following division:

U2 is an impact damper, and model is 74LS245, and major function is: deliver to each light emitting diode after input signal is driven.

U3 is an impact damper, and model is 74LS245, and major function is: deliver to each light emitting diode after input signal is driven.

U4 is a comparer, and model is TL3016CD.U5 is a counter, and model is 74VHC4040N.The circuit function that U4 and U5 form is: with the analog signal conversion of input is digital signal and frequency division.

U6A, U6B, U6C and U6D are Sheffer stroke gate, and model is 74HC00.The circuit function that U6A, U6B, U6C and U6D form is: input signal is carried out negating then with computing.

U7A, U7B, U7C and U7D are Sheffer stroke gate, and model is 74HC00.The circuit function that U7A, U7B, U7C and U7D form is: input signal is carried out negating then with computing.

U9 is a digital to analog converter, and model is TLC5620CN, and major function is: finish the conversion of digital signal to simulating signal.

U10 is an operational amplifier, and model is LM324, and major function is: finish the enlarging function to signal.

JP1 is a jumper wire device, and major function is to finish the test function of circuit.

D1～D16 is a light emitting diode, the pilot lamp on the respective operations panel.

S1～S8 is a button, the button on the respective operations panel.

Frequency measurement with the principle of work of Keyboard Control module is: the input simulating signal is exported the square wave corresponding with its frequency behind comparer, pass through the counter frequency division again, just can be measured by single-chip microcomputer U1.

(0.1Hz～100MHz), rangeability is big, and (0.1V～2.2V), and contain DC component so shaping circuit adopts high-speed comparator U4 to realize, adopts the generating positive and negative voltage power supply because the frequency range broad of input signal.The reference voltage of comparer U4 is provided by 8 bit serial digital to analog converter U9, and concrete numerical value is obtained signal sampling by the sample circuit of single-chip microcomputer U17 control.Signal after the shaping is through programmable frequency divider, and make signal through an optional low pass circuit, the chatter phenomenon that comparer produces when eliminating the input low frequency signal is delivered to the T0 mouth of single-chip microcomputer U1 at last, must arrive the frequency-measurement accuracy of 4 position effective digitals by the frequency measurement or the method in the cycle of survey.Also can select watchdog timer is connected to the frequency measurement input end, with the self check and the output of proofreading and correct watchdog timer.

As shown in Figure 6, LCD MODULE of the present invention mainly comprises liquid-crystal controller U11, LCD U13, storer U12 and negative pressure generator U29, wherein liquid-crystal controller U11 interconnects with LCD U13 and storer U12 respectively, and negative pressure generator U29 links to each other with LCD U13.

Each components and parts of following division:

U11 is a liquid-crystal controller, and model is SED1335FOA, and major function is: realize the control function to LCD.

U12 is a storer, and model is 62256, and major function is: text that buffer memory will show and figure.

U13 is a LCD, and model is LCD160160, and major function is: finish the demonstration to contents such as text and figures.

U29 is a negative pressure generator, and model is VOLTAGE100V, and major function is an output-100V supply voltage.

The principle of work of LCD MODULE is that single-chip microcomputer U17 will data presented send to liquid-crystal controller U11, and is cached among the storer U12, controls LCD U13 then and finishes Presentation Function.

Liquid-crystal controller U11 hardware of the present invention constitutes can be divided into the MPU interface portion, the drive division of internal control portion and driving LCM, can be under very high frequency of operation the instruction code sent of decipher MPU rapidly, parameter is inserted in the corresponding registers, and is triggered corresponding logic function circuit operation.Control part can be managed 64K byte display random access memory, manages built-in character generator and character generator CGRAM or the EXCGROM that extends out.Among Fig. 6, the Wave data that single-chip microcomputer U17 will show is delivered among the liquid-crystal controller U11, finishes demonstration work by liquid-crystal controller U11 control LCD U13 again.

Single-chip microcomputer U17 at first slightly samples to input signal, the output intermediate value is as the reference voltage of high-speed comparator U4, realize shaping by high-speed comparator U4, deliver to single-chip microcomputer U1 frequency measurement through programmable frequency divider again, single-chip microcomputer U17 receives the frequency measurement result of single-chip microcomputer U1 from serial ports, determine sample mode according to incoming frequency, and control precision interval clock generation circuit provides sampling clock for analog to digital converter U16.Then under the control of sampling clock, CPLD produces storage address, analog to digital converter U16 sampled data is write static memory U15 with programmed control frequency, after writing full 256 points, the control of static memory U15 is handed to single-chip microcomputer U17 by data selector, handle sampled data and liquor charging crystal display U13 demonstration by it.LCD U13 goes up waveform, frequency and the amplitude of shows signal simultaneously.

As shown in Figure 7, workflow of the present invention is as follows:

At first, single-chip microcomputer U17 is used as the voltage benchmark of comparer U4 through the amplitude of the simulating signal of waveform sampling and processing module collection input.At this moment, accuracy requirement is not high, as long as know the approximate range of the amplitude of input simulating signal, is called thick sampling.Single-chip microcomputer U17 delivers to single-chip microcomputer U1 with this voltage magnitude by serial ports, and single-chip microcomputer U1 handles this voltage magnitude, and changes the reference power supply port that analog reference voltage is delivered to comparer U4 into by digital to analog converter U9.Just can accurately measure the frequency of input signal this moment.

Secondly, single-chip microcomputer U1 is transmitted back to single-chip microcomputer U17 with the frequency analog signal that records by serial ports and determines suitable sample mode, if signal frequency is lower than 1.25MHz, then adopt the real-time sampling mode, if the frequency of signal is higher than 1.25MHz, then adopt the equivalent sampling mode, in the real-time sampling mode, for making the waveform that collects accurate as far as possible, system will be divided into three frequency ranges by following signal again, in each frequency range, produce a certain fixing reference clock, sample, specifically be provided with as follows in conjunction with corresponding frequency division by the watchdog timer circuit:

(1) frequency input signal is 1Hz～1KHz, provides 40KHz sampling clock by single-chip microcomputer U17.

(2) frequency input signal is 1KHz～1MHz, and U21 provides 40MHz sampling clock by the watchdog timer generator.

(3) frequency input signal is 1MHz～1.25MHz, and U21 provides 50MHz sampling clock by the watchdog timer generator.

When signal frequency during greater than 1.25MHz, system adopts the mode of equivalent sampling.

The incoming frequency scope of equivalent sampling is 1.25MHz～80MHz, for the waveform that makes reproduction is tried one's best accurately, in the system design in 1.25MHz～40MHz range of signal weekly the phase adopt a point, per two cycles adopt a point and reappear waveform in 40MHz～80MHz range of signal.Be that the sample frequency scope will be between 1MHz～40MHz, and controlled little step value is arranged.

Because the reference frequency output of watchdog timer generator U21 is 25MHz～400MHz, therefore need adds frequency dividing circuit low frequency part is expanded.Simultaneously, the analog to digital converter U16 that selects for use in the native system is TLC5540, and the scope of its switching rate is 5MSPS～40MSPS, so the low side sampling rate can be restricted, can design and adopt the mode of control static memory U15 writing speed to control sampling rate.Take all factors into consideration, adopt the CPLD device in the system, with the FOUT frequency of the TEST of watchdog timer generator U21 output through program control two-divider, offer analog to digital converter U16 as the CLK frequency of operation on the one hand, on the other hand again through program control two or five decade frequency dividers control static memory U15 writing speed, as the sample frequency of low-side signal.

The 3rd, after single-chip microcomputer U17 chose sampling clock, watchdog timer generator U21 delivered in the control command word that just will produce clock, wait for several milliseconds then after the inquiry this chip can operate as normal.Under watchdog timer generator U21 operation normal condition, start able to programme patrolling and seize device U18 and carry out collecting work.

At last, able to programme patrol seize device U18 static memory U15 finished 256 collecting works after, notice single-chip microcomputer U17 takes data away, single-chip microcomputer U17 handles these data according to the difference of the mode that adopts, and obtains the suitable LCD U13 that delivers to and show behind data presented form on the LCD U13.

This signal source adopts the digital technology design, has the precision height, with convectional signals source in the market characteristics simple to operate is arranged relatively.

Figure 8 shows that the control panel of signal source equipment of the present invention, in control panel as shown in Figure 8, the panel left part is a LCDs, amplitude, frequency and the waveform of shows signal in this screen.The button of panel right part and knob (from top to bottom, from left to right) are described as follows:

1) " FREQUENCY ": frequency trim knob.

The frequency trim knob links to each other with J7.4 (4 pins of J7) in Fig. 3 circuit diagram.

2) " R/P ": the duty cycle adjustment knob, be used with " ON R/P " button, when " ON R/P " button by fashionable, the R/P pilot lamp is bright, dutycycle is adjustable in 10%-90%; When " ON R/P " button when going out, the R/P pilot lamp goes out, dutycycle is 50%.

The duty cycle adjustment knob links to each other with J7.1 (1 pin of J7) in Fig. 3 circuit.

" ON R/P " button links to each other with S4 in Fig. 5 circuit.

The R/P pilot lamp is bright to link to each other with D15 in Fig. 5 circuit.

3) " DC LEVEL ": the direct current offset adjusting knob, be used with " ON DC " button, when " ON DC " button by fashionable, DC LEVEL pilot lamp is bright, DC level from-10V～+ adjustable in the 10V; When " ON DC " button when going out, DC LEVEL pilot lamp goes out, DC level is zero.

The direct current offset adjusting knob links to each other with J7.2 in Fig. 3 circuit.

" ON DC " button links to each other with S8 in Fig. 5 circuit.

DC LEVEL pilot lamp links to each other with D7 in Fig. 5 circuit.

4) " AMPLITUDE ": the amplitude knob is used to regulate the amplitude of output signal.

The amplitude knob links to each other with J7.3 in Fig. 3 circuit diagram.

5) " RANGE-Hz ": frequency range is selected

" HF " button is whenever pressed once, and frequency range is to one grade of high frequency conversion, and corresponding shelves pilot lamp is bright, divides six grades, and is capable of circulation." LF " button is whenever pressed once, and frequency range is to one grade of low frequency conversion, and corresponding shelves pilot lamp is bright, divides six grades, and is capable of circulation.

" HF " button links to each other with S2 in Fig. 5 circuit diagram.

" LF " button links to each other with S1 in Fig. 5 circuit diagram.

Six grades of pilot lamp link to each other with D9, D10, D11, D12, D13, D14 in Fig. 5 circuit diagram respectively.

6) " EXT ": survey button outward, bright by fashionable outer survey pilot lamp, LCDs shows from the signal waveform and the parameter of the input of " EXT SIGNAL " port.

The outer button of surveying links to each other with S6 in Fig. 5 circuit diagram.

The outer pilot lamp of surveying links to each other with D8 in Fig. 5 circuit diagram.

" EXT SIGNAL " input end links to each other with J4 in Fig. 3 circuit diagram.

7) " FUNCTION ": function button, be used for waveform and select, can select sine wave, square wave or triangular wave.Whenever press waveform of linear transformation, and corresponding waveform pilot lamp is bright, divides three kinds, capable of circulation.

Function button links to each other with S3 in Fig. 5 circuit diagram.

The waveform pilot lamp links to each other with D1, D2, D3 in Fig. 5 circuit diagram respectively.

8) " SPSS ": single pulsation button, press once and then export a single pulse signal from " SPSS OUT " fracture.

Single pulsation button links to each other with S7 in Fig. 5 circuit diagram.

" SPSS OUT " port links to each other with J7.5 in Fig. 3 circuit diagram.

9) " FM " frequency sweep button, bright by fashionable pilot lamp, the output swept-frequency signal.

The frequency sweep button links to each other with S5 in Fig. 5 circuit diagram.

The frequency sweep pilot lamp links to each other with D16 in Fig. 5 circuit diagram.

10) " ATTENUATOR ": the decay button, conversion attenuation multiple when pressing, the pilot lamp of decaying accordingly is bright, divides fourth gear, and is capable of circulation.

The decay button links to each other with J7.6 in Fig. 5 circuit diagram.

The decay pilot lamp links to each other with D4, D5, D20, D21 in Fig. 3 circuit diagram respectively.

11) " POWER ": power switch is pressed into to opening.

The power switch general supply links to each other.

12) " TTL ": Transistor-Transistor Logic level square wave output port.

Transistor-Transistor Logic level square wave output port links to each other with J7.7 in Fig. 3 circuit diagram.

13) " OUTPUT ": signal output part.

Signal output port links to each other with J7.8 in Fig. 3 circuit diagram.

Claims (6)

1, a kind of derived digital signal with the waveform demonstration, it is characterized in that it comprises controller, waveform sampling and processing module, program control watchdog timer module, frequency measurement and Keyboard Control module and LCD MODULE, described controller links to each other with Keyboard Control module and LCD MODULE with processing module, program control watchdog timer module, frequency measurement with waveform sampling respectively, input signal is sent in waveform sampling and processing module and the frequency measurement module, and program control watchdog timer module links to each other with processing module with waveform sampling simultaneously.

2, the derived digital signal of band waveform demonstration according to claim 1 is characterized in that described controller comprises two single-chip microcomputers and impact damper, and wherein a single-chip microcomputer links to each other with peripheral circuit by impact damper, joins by serial ports and another single-chip microcomputer.

3, the derived digital signal of band waveform demonstration according to claim 1, it is characterized in that described waveform sampling and processing module comprise that static store, analog to digital converter, able to programme patrolling seize device, described static store is seized device and is linked to each other with able to programme patrolling, and analog to digital converter is then seized device and linked to each other with able to programme patrolling with static store respectively.

4, the derived digital signal of band waveform demonstration according to claim 1 is characterized in that described watchdog timer module comprises light emitting diode, watchdog timer generator, level transferring chip and optocoupler, and wherein optocoupler and triode are formed signal isolation circuit.

5, the derived digital signal of band waveform demonstration according to claim 1, it is characterized in that described frequency measurement and Keyboard Control module be made up of two impact dampers, comparer, counter, digital to analog converter, operational amplifier and light emitting diodes, wherein comparer links to each other with counter.

6, the derived digital signal of band waveform demonstration according to claim 1 is characterized in that described LCD MODULE comprises liquid-crystal controller, LCD and storer, and wherein liquid-crystal controller interconnects with LCD and storer respectively.

Images