SU547030A1 - Digital signal generator - Google Patents

Description

one

The invention relates to radio engineering and may be used when measuring parameters and setting up digital communication systems.

A digital signal generator is known that contains a source of pulses with a constant repetition frequency that controls a digital divider. The frequency of the input pulses is divided into exact integers. The output signal of the divider is fed to a reversible counter, subjected to digital-analogue conversion, resulting in an analog signal that is close to sinusoidal 1.

This generator has narrow functionality and relatively low accuracy.

A known digital signal generator containing a master oscillator, the output of the latter is connected to the input of the modulator, another input of which is connected to the output of the generator of the modulating signals and to the input of the first forming device, and the output of the modulator is connected to the input of the second forming device, while the output of the first forming device connected through a reversible counter and a control device to the inputs of the elements of coincidence, the digital-to-analog converter 2.

This digital signal generator has a low digital accuracy, represented by signals and a relatively narrow frequency range of output signals.

In order to improve the accuracy of the digital representation of signals and expand the frequency range of the output signals, the proposed digital signal generator additionally includes the Ban Prohibition element and the trigger with separate inputs, whose inputs are not associated with the outputs of the coincidence elements, the trigger outputs with split inputs are connected via a reverse counter to the inputs of the prohibition elements, the other inputs of which are connected to the output of the first forming device, and the outputs of the prohibition elements are connected to the inputs of the digital-analog conversion the driver, with one of the outputs of the control device connected to the input of a modulator of the modulating signals.

The drawing shows a functional electrical circuit of the proposed digital signal generator.

The digital signal generator contains a pulse generator 1, which contains a master generator 2, the output of which is connected to the input of the modulator 3, another input of which is connected to the input of the first forming device 4 and connected to the output of the generator 5 of modulating signals, and the output of the modulator 3 is connected to the input of the second formative

device 6. The output of the latter is connected to interconnected inputs of the reversible counter 7 and the control device 8, in which the first output is connected to the generator input 5 of the modulating signals of the pulse generator 1, the second output to the OD 10 of the inputs of the condominium element 9, and the third output connected to one of the inputs of the element 10 matches.

The direct outputs of the reversing counter bits are: 1 ka 7 are connected to the ale gg inputs 9 matches and through prohibition elements 11–15 to the output terminals 16 and to the inputs of the digital to analog converter 17, the output of which is connected to the output terminal 18. Inverted outputs of the reversing bits the counter 7 is connected to the inputs of the element 10. The other inputs of the prohibition elements 11-15 are connected to the outputs of the nerve-controlled unit 4 of the pulse generator 1. B x xodes of elements 9 and 10 are connected respectively to the zero and single inputs of trigger 19 with separate inputs, and its outputs are connected with cranking inputs of the reversing counter 7. Counter 7 and trigger 19 with separate inputs are connected to reset terminal 20 of the circuit.

The digital signal generator works as follows.

The carrier oscillation from the output of the master oscillator 2 of the pulse generator 1 is fed to one of the inputs of the modulator 3 of the pulse generator 1, in which it is thrust through the angular modulus. At its other input there is a modulating signal from the generator 5 of the modulating signals of the geyrator 1 pulses.

The shape of the modulating signal is selected by the power supply of the control device 8 by connecting the corresponding signal from the generator 5 of the modulating signals to the modulator 3 and depends on what functional dependence is required to receive in digital form. So, for example, in order to digitally represent a harmonic wave, the modulating signal, which is from the generator 5 of the modulating signals to the modulator 3 in the generator 1 of the emulsions, must be harmonic.

From the modulator 3 of the pulse generator 1, the digital signal is fed to the second shaping device 6 of the pulse generator 1, the output of which at time points corresponding to zero values of the current phase of the modulated oscillation, and a sequence of time-modulated pulses received at the counting input of the reversible counter 7. The coordination of the average number of pulses for the period of the modulating signal with the capacity of the reversible counter 7 takes place by means of feedback between the output of the second About the device 6 of the generator 1 of pulses and the generator 5 of the modulating signal of the generator 1 of emuls through the control device 8. Coordination is achieved by changing the parameters of the modulating signal generated by the generator 5 of the modulating signal of the generator of 1 pulses.

A reset pulse, applied to the reset circuit terminal 20, sets the reversible counter 7 to the initial state (“O), and the flip-flop 19 with separate inputs returns to the“ 1 ”state, while the output signal from the flip-flop 19 with separate inputs provides a dir. Monitoring the operation of the reversible counter 7.

When the reversible counter 7 reaches the state “11111, at the output of element 9, an immo- lution is activated, the changing state of the trigger with separate inputs and the opposite one. At this point, the reversible counter 7 starts to work in subtraction mode.

Upon the reversal counter 7 of state "00000", a pulse is generated at the output of element 10, which, by means of a trigger 19, switches the reversible counter 7 to the addition mode. The process then repeats. This mode takes place if through resolver 8 on both elements 9 and 10 resolution levels are iodine.

The need for such a regime is determined by the fact that when forming digital signals reflecting some functional dependencies, iaiymer is sinusoidal, triangular, the function increases (decreases) during one part of the period, and decreases (increases) during another part of the period.

When generating signals, reflecting

only an increasing (decreasing) function, and the element 9 from the control device 8 receives the resolving (overriding) level, and the element 10 receives the incipient (permitting) and the reversible counter 7 operates in the addition (subtraction) mode.

The pa outputs of the reversible counter 7 form a sequence of numbers corresponding to the conditional level measures, signals, reflecting the chosen functional dependence.

In order to prevent the occurrence of erroneous numbers, the transition by the reversible counter 7 states 11III and 00000, due to the final response time of the bits of the reversible counter 7 on the prohibition elements 11-15, the gating of signals output to the output terminals 16 is produced.

Gating pulses are obtained from the signals of the generator 5 of the modulating signals of the generator 1 nmluls using the first shaping device 4 of the generator

1 IM: YULSOV.

In addition to the input terminals 16, the digital signal is connected to the input of the digital-to-analog converter 17, and at the output terminal 18 synchronously with the digital signal fed to the output terminals 16, an analog signal is generated reflecting the selected functional relationship.