SU1181145A2 - Analog-to-digital converter - Google Patents

Abstract

ANALOG-DIGITAL CONVERTER on auth.St. No. 1091332, characterized in that, in order to improve noise immunity, the second, third and fourth elements of OR, the second counter, the sixth trigger, the fifth, sixth and seventh elements of the match, the first and second pulse formers, the second, third and fourth elements are NOT, while the input of the second element is NOT combined with the first input of the fifth coincidence element and connected to the quantization pulse bus, the first inputs of the second, third and fourth elements OR are combined and connected to the output of the second element NOT, the second input of BTopo the OR element roi is combined with the second input of the first match element and connected to the output of the fourth OR element, the second input of the third OR element is combined with the second input of the fourth OR element and connected to the output of the second pulse shaper, whose input is connected to the output of the fourth HE element, whose input is connected to the output of the seventh coincidence element, the first input of which is connected to the output of the first pulse shaper, the second input of the seventh coincidence element is combined with the third input of the third element and OR is connected to the output of the sixth trigger, the first input of which (A is connected to the output of the fifth coincidence element, and the second input is connected to the output of the sixth matching element, the first input of which is combined with the input of the second counter and connected to the output of the second OR element, first output The second counter is connected to the second input of the fifth coincidence element, the second output is connected to the second input (the sixth matching element, the output of the third OR element is NOT connected to the 4th input of the first pulse generator through the third element.

Description

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The invention relates to a pulse technique and can be used in automation and computing devices.

The purpose of the invention is to increase the noise immunity of the analog-digital converter.

FIG. 1 shows the structural scheme of the proposed converter; in fig. 2 is a timing diagram explaining the operation of the device} in FIG. 3 is a time diagram of the process of recovering 1 quantization pulses.

The proposed analog-to-digital converter contains a threshold device 1, a discriminator 2 of the moment of transition through the video signal maximum, the first trigger 3, the first matching element 4, the second trigger 5, the first delay element 6, the second matching element 7, the third trigger 8, the third matching element 9, quarter trigger 10, second delay element 11, first I-UIli 12 element, 13 pulse generator, fourth match element 14, first counter 15, five trigger 16, first HE element 17, quantization pulse bus 18, input signal bus 19, bus 20 threshold signal, second 21, third 22 and fourth 23 elements NOT, second 24, third 25, quarter 26 OR elements, second counter 27, fifth 28, sixth 2 seventh 30 match elements, sixth trigger 31, first 32 and second 33 drivers pulses, the output bus 34 ..

Analog-to-digital converter works as follows.

The threshold device 1 (Fig. 2) passes to the input of the discriminator 2 the moment of transition through the maximum of the video signal only that part of the input video signal from the detector output at the output channel that exceeds the quantization threshold specified by the voltage at its second input (Fig. 2a). On the output of the discriminator 2, at the moment corresponding to the beginning of the decay of the video signal, the pulse of FIG. 26, the overturning trigger 3 (FIG. 2e). The channel of signal processing of the first target starts working: trigger 3 - element 4 matches - trigger 5 - delay element 6.

When entering through the elements 17, 21-33 Tia, the second input of the element 4 is the coincidence of the quantization pulse (Fig. 2 g)

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at its output, an impulse appears, overturning the trigger 5 (Fig. 2h). The same pulse, passing through the delay element 6 (Fig. 2e), returns the triggers 3 and 5 to the initial state (Fig. 2e, h) and through the OR 12 element to the output of the analog-to-digital converter comes the standard pulse (Fig. 2i) . The duration of this pulse is equal to the delay time in delay element 6, and the temporal position is determined by the quantization pulse corresponding to the input video signal.

Simultaneously with the inclusion of the processing channel of the first target, caused by the appearance of the signal at the output of the discriminator 2, trigger 3 sets the resolving potential at the inputs of the coincidence element 14, the counter T5 and the trigger 16, the signals from the generator output 13 begin to flow to the counting input of the counter 15, Repetition Period i generator pulses (FIG. 2c and the conversion factor K. of the counter 15 are selected so that the trigger 16 is set to the Log state, 1 after a time interval that exceeds the maximum possible values of the pulse duration and the output of the discriminator 2, the change in the duration of this pulse may be, for example, due to fluctuations in power supply voltage, temperature drift, etc.

Through the periods of the pulse generator 13, at the output of the counter 15 (its higher bit) a counted front appears, which sets the trigger 16 to the Log state. 1 (FIG. 2g), Destructive potential (Log. 1), the output of trigger 16 is fed to the input of the NOT 17, where it is inverted (Log. O), the inhibitory potential. O) from the output of the element NOT 17 closes the element 14 to coincide, the flow of the generator pulses 13 to the input of the counter 15 stops, and the trigger 16 remains in the Log, 1 state. The voltage from its output (Log. 1) is fed to the second input of the element 7 coincidence. , preparing the channel for processing the signal of the second circuit: element 7 coincidence - trigger 8 - element 9 coincidence - trigger lO - delay element 11. 3 The arrival of the signal from the second circuit at this moment, when the first signal is received by processing the signal of the first circuit, initiates the operation of the second channel. The work of the second channel is analogous to the work of the first signal processing channel Through the OR 12 element, standard pulses are passed to the output of the analog-digital conversion of the bodies. After the end of the signal processing cycle in the signal processing channel of the first circuit, the output of the trigger 3 establishes the voltage Log. Oh, (fig. 2e). This voltage is applied to the installation inputs of the counter 15 and the trigger 16, resetting them to the zero state. The device completes the processing of the input video signal and returns to the original connection. However, in the process of transferring not 18 to the analog-to-digital converter of quantization pulses (fig.2g in the channel for transferring quantization pulses, a malfunction may occur (fig.2k) characteristic of the channels of the exchange of pulse signals, which leads to an error of the analog-digital conversion the generator, the input sequence of quantization impulses (fig. 2d and 2k) via bus 18 goes to the second element NOT 21. The sequence of pulses that is inverted is quantum not fed through the second element OR 24 to the second counter 27. The first pulse forms The second counting 27 at its first output (FIG. 2L) is synchronized by the input sequence of quantization pulses and through an additional matching element 28 arrives at the first input of trigger 31. From the second output of counter 27, the sixth 29 matches the second input of trigger 31 to the same polarity (Fig. 2m) and the trigger 31 is triggered by applying from its single output to the third input of the third element OR 25 a positive voltage drop (Fig. 2n) Simultaneously with the positive voltage drop, the third input of the first input of the OR 25–454 element is inverted by the HE 2 I input sequence of quantization pulses. At the second input of the OR 25 element, at the initial moment of time, a positive signal from the closed output of the second form- ing signal arrives. pulse 33 pulse-cell The output signal of the element OR 25, inverted by the element HE 22, is fed to the input of the first driver of the 32 pulses, opening it with negative differences of a sequence of quantization pulses, i.e. back edges of received quantization pulses. Having opened, the shaper 32 detects negative polarity pulses of a duration, thereby forming a sequence of pulses (Fig. 2n). This sequence arrives at the first input of the coincidence element 30, the second input of which receives a positive voltage drop from the trigger output 31.1. The output signal of the coincidence element 30, inverted by an additional element NOT 23, is fed to the input of the second pulse shaper 33, opening it. Having opened, the pulse shaper 33 forms a negative-polarity pulse of a length of -. bg, forming a sequence of pulses (Fig. 2p). This sequence of pulses is fed to the second inputs of the OR elements 25 and 26, to the first input of which the input sequence of quantization pulses is also inverted by the NOT element 21. The output of the element OR 26 is fed to the second input of the element RSH 24 and to the second inputs of the elements 4 and 9 coincidence. If there is no failure (pulse propagation) in the quantization pulse transmission channel, all input quantization pulses through the NOT 21 element arrive at the OR 26 element, from the output of which 4 and 9 coincidence elements arrive, i.e. From the output of the OR 26 element, the elements 4 and 9 of the coincidence arrive either from the quantization pulses of the sequence or from the generated quantization pulse.

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Claims (1)

ANALOG-DIGITAL CONVERTER by ed. No. 1091332, characterized in that, in order to increase the noise immunity, the second, third and fourth OR elements, the second counter, the sixth trigger, the fifth, sixth and seventh coincidence elements, the first and second pulse shapers, the second, third and fourth elements are introduced into it NOT, while the input of the second element is NOT combined with the first input of the fifth matching element and is connected to the bus of quantization pulses, the first inputs of the second, third and fourth elements OR are combined and connected to the output of the second element NOT, the second input of the second.el OR is combined with the second input of the first coincidence element and connected to the output of the fourth OR element, the second input of the third OR element is combined with the second input of the fourth OR element and connected to the output of the second pulse shaper, the input of which is connected to the output of the fourth element NOT, the input of which is connected to the output of the seventh match element, the first input of which is connected to the output of the first pulse shaper, the second input of the seventh match element is combined with the third input of the third OR element and nen with the output of the sixth trigger, the first input of which is connected to the output of the fifth matching element, and the second input is with the output of the sixth matching element, the first input of which is combined with the input of the second counter and connected to the output of the second OR element, the first output of the second counter is connected to the second input fifth element of coincidence, the second output - with the second input ('sixth · element of coincidence, the output of the third element OR through the third element is NOT connected to the input of the first pulse shaper. > ί 1181