SU741450A1 - Pulse-width function generator - Google Patents

Description

The invention relates to digitally controlled rectangular pulse generators that implement a given functional dependence of the duration of the output pulses, and can be used in control systems, willows ^{5 * * * *} automation devices and computer equipment.

A controllable generator is known, comprising a reference frequency generator connected in series, a conversion device ¹⁰ , a shaping device, three transfer devices and two sensors programming changes in the pulse duration and the intervals between pulses, and two reversible QQ counters are used to set the duration of pulses and pauses.

However, to set the law of change of the modulating function, it is necessary to have an additional external device for generating increments of the pulse and pause codes, which is a separate complex task.

A generator is also known that contains a master oscillator, a decoder consisting of two matching elements, a counter whose reset input is connected to the output of the first OR element, and a counting input to a master oscillator, an output trigger, whose inputs are connected to the outputs of the first and second decoder matching elements , a duration code sensor and an interval code sensor, the outputs of which are connected to the inputs of the first and second coincidence elements, respectively, through additionally entered OR elements, the other inputs of which are connected counter outputs, and the outputs of the flip-flop and the first input of OR introduced additional differentiating tsepiG21,

The disadvantage of the generator circuit considered is limited functionality, since for modulating the duration of the output pulses according to some law it is necessary to develop an additional external device ³ 741450 that changes the code in the pulse code sensor, which is a new task in each specific case.

The purpose of the invention is the expansion of functionality.

The specified goal, ', is achieved by the fact that in the pulse-width functional ge-. a herator containing a trigger, a crystal oscillator, an OR element, _{v A} decoder and a counter whose outputs are connected to the inputs of the decoder, a modulation frequency generator, a decoder control unit and an I element are introduced, the output of the modulation frequency generator being connected to the counter input of the trigger, with a counter reset input and with the input of the decoder control unit, the trigger output and the output of the crystal oscillator are connected to the inputs of the And element, the output of which is connected to the counter input, the outputs of the decoder control unit are connected to the resolution conductive decoder inputs and outputs of the decoder are connected to the inputs of OR gate whose output is connected to the set input latch to zero.

In FIG. 1 shows a block diagram of a pulse-width functional generator; in FIG. 2 is an example of a specific implementation of the generator circuit.

The device (Fig. 11 contains a trigger 1, from the output A of which a sequence of pulse-width modulated pulses is taken, which is the output signal of the generator. Inputs 2 and circuits are connected to the output A of trigger 1 and to the output of the crystal oscillator 3, and the output to the counting input of the rows of the counter 4 of the decoder 5, by the decoder the lower inputs of the decoder 5. The decoder 5 is connected to the inputs of the element 6 OR, the output of which is connected to the input of the zero setting of the trigger 1. The output of the modulation frequency generator 7 is connected to the counting input of the trigger'1, the input Ohm block 8 control the decoder and the input reset counter 4.

The sequence of pulses at the output A of trigger 1 can be represented as a form 50 rneT ^ nlQ is the duration of one pulse in the output sequence;

Tot L is the constant component of the pulse duration in the output sequence;

counter 4. The outputs are connected to the inputs; the outputs of the control unit8 are connected with permission—.

Outputs

- the amplitude of the variable component of the duration of the output pulses in the period;

- the law of the modulating periodic function;

- frequency of the modulating function;

- time quantization period.

function P

Let the period (for example, sinusoidal) be symmetric on. . . . . .. -------) and ^ Ο-Then, the decoder control unit 8 (Fig. 2) may contain elements 9 NOT, 10 and 11 AND, a reverse trigger 12, a decoder 13 of the control unit and a reversible counter 14. Let in the initial state, the counters 4 and 14 of the device are set to zero, the reverse trigger 12 is set to the Addition position. The trigger 1 is set to position O and pulses from the crystal oscillator 3 to the input of the counter 4 are not received. With the arrival of the first pulse from the generator 7, trigger 1 fires and the counter 4 starts to fill up. At the same time, the unit in the low order is set in the reverse counter 14, and a control potential is supplied to one of the inputs of the coincidence element of the decoder 5 through the decoder 13 of the control unit, allowing its switching when the code 4 appears in the counter (for example, the code number m). When the mth pulse from the quartz oscillator 3 arrives at counter 4, the prepared match element of the decoder 5 is triggered and, via the 6 OR element, trigger 1 is set to zero, locking the input of counter 4 and generating the first pulse of the first period of the modulated sequence A. After the pulse ends from generator 7, counter 4 is set to zero. The second pulse from the generator 7 again switches the trigger 1, and the output signal of the control unit 8 prepares the encoder 5 to the counter 4 of the rotor 7 on the function generates a pulse of maximum duration in the output sequence. At the moment of the end of this pulse of the generator 7 through the elements 9 and 11, a pulse is formed of the installation of the trigger 12 of the reverse in the position Subtraction and trigger 12 of the switch. Starting from the next pulse of the generator 7 until the end of the period of the modulating function, the reverse counter works for subtraction, preparing the matching elements of the decoder 5 a new matching element for highlighting the new code in, etc. The last impulse to the gene segment of growth is modulating in the reverse order for a symmetric modulation law is formed, at the end of the trigger period. 12 reverse switches back to addition, etc. Using up-down counter 13 make it possible to obtain 5 wish to set up a symmetric modulation law to reduce the required number of elements matches decoder 5. For the formation of asymmetrical on the period of the modulating law uses the same control unit ^10, but in this case, the switching in the counter counting direction

1-4 does not occur, and at the end of each modulation period, it is necessary to set the counter 14 of the control unit 8 to the initial ^{, 5th} state. The necessary parameters for constructing the proposed device are determined from equation 1 as follows: we find Tft / T is the number of pulses in the period of the modulating function, ²⁰ where Tq = 4 / · · From here is the frequency of the modulation generator £ _g en.mod ⁼ 1 / T

In addition, the value T ^ / T determines the number of coincidence elements of the decoder ^{25. The} number of bits of the main counter 3 is selected based on the required modulation law and the required accuracy of reproduction of this law; the frequency of the crystal oscillator is determined by Yu according to the formula where O is the decryptable code in the counter, ³⁵ corresponding to the duration of the maximum pulse in the period.

We also note that if Т _о И is equal to zero, then a trigger of a function sign must be entered into the decoder control unit, the state of which will be determined by the signals from the outputs of the decoder 13 of the control unit 8.

Claims (2)

The invention relates to square pulse generators with digital control, realizing a given functional dependence of the duration of the output pulses, and can be used in control systems, control systems and in automation and computing devices. A controlled oscillator containing a series-connected reference frequency oscillator is known. a device, a forming device, three transfer devices and two sensors, programming changes in the duration of the pulse and the intervals between pulses, and two reversible counters are used to set the pulse and pause durations. However, in order to specify the law of change of the modulating function, it is necessary to have an additional external device for generating pulse code and pause code increments, which is a separate complex task. Also known is a generator containing a master oscillator, a decoder consisting of two elements of coincidence, a counter whose reset input is connected to the output of the first OR element, and a counting input to the master oscillator, an output trigger whose inputs are connected to the outputs of the first and second elements match the decoder, the sensor code duration and the sensor code interval, the outputs of which are connected to the inputs of the first and second elements of the match, respectively, through the additionally entered elements OR, the other inputs of which connect Yeni with counter outputs, and between the trigger outputs and the inputs of the first element OR additional differentiating nennL2J are introduced. The disadvantage of the generator circuit considered is limited functionality, since for modulating the duration of the output pulses, according to any law, it is necessary to develop an additional external device, 374 stBO, changing the code in the pulse code sensor, which in each case is a new task. The purpose of the invention is to enhance the functionality. The specified target; achieved by the fact that a pulse width function generator containing a trigger, a crystal oscillator, an OR element, a decoder and a counter, whose outputs are connected to the inputs of the decoder, introduces a modulation frequency generator, a decoder control unit and an And element, with the output of the module frequency generator connected to the counting trigger input, to the counter reset input and to the input of the decoder control unit, the trigger output and the output of the crystal oscillator are connected to the inputs of the AND element, the output of which is connected to the counter input and, a decoder control unit outputs are connected to the enabling input of the decoder, and the decoder outputs are coupled to the inputs of OR gate whose output is connected to the set input latch to zero. FIG. 1 shows a structural diagram of a pulse-width function generator; in fig. 2 is an example of a specific implementation of the generator circuit. The device (Fig. 1 contains a trigger 1, the output of which is the sequence of pulse-modulated pulses, which is the generator output signal. Inputs 2 and circuits are connected to output A of trigger 1 and to the output of the crystal oscillator 3, and code to the counting input counter 4. The outputs of the bits of counter 4 are connected to the inputs of the decoder 5, and the outputs of the control unit of the decoder 8 are connected to the enabling inputs of the decoder 5. The outputs of the decoder 5 are connected to the inputs of the 6 OR element, the output of which is connected to the input to zero trigger 1. The output of the modulation frequency generator 7 is connected to the counting input of trigger 1, the input of the decoder control unit 8 and the reset input of counter 4. The pulse sequence at the output A of trigger 1 can be represented by the formula raeTmTj — the duration of one pulse in the output sequence R and the fast sequence of the component of the pulse duration in the output sequence; 0 T; is the variable amplitude component of the duration of the output pulse in the period; p is the law of modulating periodic functions; 7. - frequency of the modulating function; T - period of quantization in time. Let the function P be symmetric on a period (for example, sinusoidal) and the DGMM 0-Then the decoder control block 8 (FIG. 2) may contain the elements 9 HE, 10 and 11 AND, the trigger 12 of the reverse, the decoder 13 of the control block and the reversible counter 14. Let in the initial state, the counters 4 and 14 of the device are set to zero, the trigger 12 of the reverse is set to the Addition position. The trigger 1 is set to O and the pulses from the crystal oscillator 3 are not fed to the input of the counter 4, With the arrival of the first pulse from the generator 7, the trigger 1 is triggered and the counter 4 starts filling. At the same time, the unit in the younger bit is installed in the reversible counter 14, and the control potential is supplied to one of the inputs of the coincidence element of the decoder 5 through the decoder 13 of the control unit, allowing it to switch when a code (for example, numbers m). When m-pulse from the crystal oscillator 3 arrives at counter 4, the prepared element matches the decoder 5, and through element 6 OR trigger 1 is set to zero, locking the input of counter 4 and forming the first pulse of the first period of the modulated sequence A at the output. from generator 7, counter 4 is set to zero. The second pulse from the generator 7 again switches the trigger 1, and the output signal of the control unit 8 prepares a new coincidence element of the decoder 5 to highlight the new code in the counter 4, etc. The last pulse of the generator 7 in the area of growth of the modulating function generates a pulse of maximum duration in the output sequence. At the moment of termination of the given generator pulse 7, elements 9 and 11 form a pulse of setting the reverse trigger trigger 12 to the Subtraction position and the trigger trigger 12 of the switch. Starting from the next generator 7 until the end of the period of the modulating function, the reversible counter works on subtraction, preparing the elements of the decoder 5 in the reverse order for generating a symmetrical modulation law. At the end of the period trigger. 12 reverse switches back to addition, etc. Using a reversible counter 13 allows for obtaining a symmetric modulation law to reduce the required number of elements of the decoder 5 matches. To form an asymmetric modulating law for the period of the modulating law, the same control unit is used, but in this case the counting direction does not switch in counter 3 of the modulation period, it is necessary to set the counter 14 of the control unit 8 to the outgoing. condition. The necessary parameters for the construction of the proposed device are determined from equation 1 as follows: find T / T - the number of them-V, -... pulses in the period of the modulating function, where T. From here, the frequency of the modulation generator f (.od 1 / T is found. In addition, the value Tsi / T determines the number of coincidence elements of the decoder 5. The number of bits of the main counter 3 is selected based on the required modulation law and the required accuracy of reproduction of this law } the frequency of the quartz oscillator is determined by the formula EKBWC / VT where O is the code to be decoded in the counter, corresponding to the duration of the maximum pulse in the period. Note also that if RT TRL is zero, then the descriptor control unit must be entered igger of the function sign, the state of which will be determined by signals from the outputs of the decoder 13 of the control unit 8. Claims of the invention Pulse width functional generator containing a trigger, a quartz oscillator, an OR element, a decoder and a counter, the outputs of which are connected to the inputs of the decoder, characterized by that, in order to expand its functionality, a modulation frequency generator, a decoder control unit and an I element are inputted into it, and the output of the modulation frequency generator is connected to the counting input trigger The trigger output and the output of the crystal oscillator are connected to the inputs of the element I, the output of which is connected to the input of the counter, the outputs of the control module of the decoder are connected to the enable inputs of the decoder, and the outputs of the decoder are connected to the inputs of the element OR whose output is connected to the trigger setup input to zero. Sources of information taken into account in the examination 1. USSR author's certificate number 439901, cl. H 03 K 1/12, 1972. 2. Author's certificate of the USSR 452056, class, H 03 K 1/18, 1973.