SU970678A1 - Analogue-digital converter - Google Patents

Description

(54) ANALOG-DIGITAL CONVERTER

one

The invention relates to computing and can be used to convert a voltage into a code when building digital reception paths. five

A device is known that contains a voltage transforming sensor, compares a device, code to voltage transducers of order and mantissa, a control circuit, 10 clock generator, a decoder, an encoder 1.

In this device, the value of the output code as a function of the input voltage is in a logarithmic j dependence, which makes it possible to reduce the number of bits of the output code as compared to linear converters.

A disadvantage of this device is the low accuracy of converting low level signals with a large dynamic range of input voltages.

The closest to the proposed 25 is a device containing a series-connected amplifiers, the output of each of which is connected to the counter 2.

A disadvantage of the known device is the insufficiently high conversion accuracy due to the presence of a large number of threshold devices having variations in the threshold of operation (the number of threshold devices is equal to the number of conversion steps).

The purpose of the invention is to improve the accuracy of the conversion.

This goal is achieved by the fact that an analog-to-digital converter containing series-connected amplifiers, a detector, a counter are connected to the output of each of them, a decoder and a switch connected in series, a threshold device and a counter triggering device are input, the switch inputs are connected to the outputs of the respective detectors, the first output of the device for starting the counter is connected to the gate input of the decoder, the second is connected to the counter input of the counter, the outputs of which are connected to the inputs of the decoder ora, and the outputs of the decoder are connected to the control inputs of the switch.

The counter start device is made on three elements And, the trigger and clock generator, the first output of which is connected to the first inputs of the first and second elements And, the second output to the first input of the third element And, the third output to the first output of the device to start the counter connected to the second input of the first element And, the output of which is connected to the S-input of the trigger and to the second input of the second element And, the output of which is connected to the R-input of the trigger, the single output of which is connected to the third input of the third The element I, the output of which is connected to the second output of the device for starting the counter.

FIG. 1 shows the functional diagram of the analog-digital converters; in fig. 2 - functional diagram of the proposed device.

The device contains amplifiers 1, detectors 2, switch 3, threshold, full device 4, counter start device .5, counter b, decoder 7, elements 8-10, trigger 11, generator 12 clock pulses (GTI).

The device works as follows.

When the input voltage is close to zero, only the switch 3 key periodically opens, connecting through the detector 2 to the input of the threshold device .4 the output of the last amplifier 1. As the input voltage rises to a value above the threshold of the threshold device 4, the threshold of the threshold device so that at the minimum input voltage the threshold. device when connected to the output of the most sensitive amplifier worked), the latter will work and the device

5starting the counter will transfer the counter

6in the next state. At the output of the decoder 7, a pulse is formed (the formation of pulses at the output of the decoder 7 is ensured by the fact that the gate input of the decoder receives strobe pulses from the output of the counter start device 5) connecting the output of the penultimate amplifier to the input of the threshold device 4. If the voltage arriving at the input of the threshold device 4 from the output of this amplifier, exceeds the threshold of the threshold device 4, it will trigger and the start device 5 of the counter will turn the counter 6 into a desired state. In this case, a pulse is formed at the output of the decoder 7, which connects the output of the next amplifier to the input of the threshold device 4. This switching continues until the voltage at the input of the threshold device 4 coming from the output of the corresponding amplifier

exceeds the threshold. If the voltage from the output of the connected amplifier does not reach the threshold of the threshold device 4, then the switch key 3,

the output of this amplifier opens periodically, but the counter 6 does not go to the next state. This counter state corresponds to the number of transducer steps

0 The device operates as follows (Fig. 2).

When voltage 8 is input to the input of the first element 8 (the analog-digital converter threshold device 4 has triggered) the pulse from the output of the GTI 12 passes through the first element I and sets the trigger 11 to state 1, thereby passing through the third element

0 and 10 pulses from the output of the GTI 12 to the output of the counter trigger device to start the counter. The pulse from the output of the GTI 12 enters the gate input of the decoder 7. If available

5 at the input of the first element AND 8 of the voltage O (the threshold device 4 did not operate) the pulse from the output of the GTI 12 passes through the second element AND 9 and sets the trigger 11 to the state

0 0, thus providing a prohibition for passing through the third element I 10 of the pulse from the output of the GTI 12 to the output of the meter trigger device. The time spacing of the pulses from the GTI outputs allows the time spacing of the switching of counter 6 and the connection of the outputs of the amplifiers to the input of the threshold device 4.

Claims (2)

1. An analog-to-digital converter containing a series-connected amplifiers, to the output of each of which a detector is connected, a counter, characterized in that, in order to increase the conversion accuracy, a decoder and series-connected are entered into it switch, threshold device and the meter triggering device, the switch inputs are connected to the outputs of the respective detectors, the first output of the meter trigger device is connected to the gate input of the decoder, the second is connected to the counter input of the counter, whose outputs are connected to the decoder inputs, and the decoder outputs are connected to the switch control inputs. 0 2. The converter according to claim 1, which is based on the fact that the device for starting the counter is made on three elements AND, the trigger and the generator of clock pulses, the first output 5 which is connected to the first inputs the first and second element And, the second output to the first input of the third element. And, the third output to the first output of the device that starts the counter, the input of which is connected to the second input of the first element And whose output is connected to the S input of the trigger and to the second input of the second element And, the output of which is connected to the R-input of the trigger, a single output of which is connected to the second input of the third element And, the output of which is connected to the second output of the device that starts the counter. Sources of information taken into account in the examination 1. Authors certificate of the USSR 364091, cl. H 03 K 13/17, 1968. 2. Authors certificate of the USSR 566343, cl. H 03 K 13/02, 1972 (prototype). f 8. F-1 , P R12 (pue.i