SU947960A1 - Bipolar a-d converter with automatically scaling input signal - Google Patents

Description

entered D} 1 secret divider, first and second threshold elements and a scale counter, the second input of the analog storage unit is connected to the input bus, and the output is connected to the input of a discrete divider, the group of control inputs of which is connected to the second group of control outputs of the control unit, The second output of which is connected to the first input of the key, the output of which is connected to the second input of the comparison unit, and the second input to the output of the discrete divider and the first inputs of the first and second threshold elements, the second inputs to They are connected respectively to the second and third outputs of the D / A converter, the outputs of the first and second threshold elements are connected respectively to the first and second inputs of the 1Sh element, whose output is connected to the second input of the control unit, the third output of which is connected to the scale counter. which is integrated with the group of information outputs of the control unit and is connected to the output bus.

The drawing shows a structural electrical circuit of the device.

The device contains an analog storage unit 1, a discrete deltel 2, a key 3, a comparison unit 4, a digital-to-analog converter 5 g control block b, the first threshold element 7, the element OR 8, a scale counter 9, the second threshold element 10.

Analog-to-digital converter works as follows.

The cycle of the analog-digital driver begins with the arrival of a clock pulse from the control unit 6 to the analog storage unit 1, the latter being set to the storage mode of the instantaneous value of the output signal. The memorization process lasts for the first cycle, the rest of the time unit 1 is in the storage mode.

A sample of the analog signal is fed through a discrete divider 2 to the first inputs of the first and second threshold elements 7 and 10, to the second inputs of which are respectively the positive and negative reference voltages from the digital-analog converter 5. The transfer coefficient of the discrete divider at the beginning of each conversion cycle is set with control block 6 is equal to one.

If the input signal of threshold 7 and 10 is absolute in magnitude less than one of the reference voltages supplied from the digital-analog converter 5, the transfer ratio of the discrete divider 2 is kept equal to one. When the input signal exceeds the threshold values of the reference voltages of elements 7 and 10, one of them gives the command, through the OR 8 element, to the control block 6 to decrease the transmission coefficient of the discrete divider 2 by half. The transfer coefficient of the discrete divider 2 decreases stepwise by a factor of 2 where n is the scaling factor, according to the signal from the control block b, until the input signal of the threshold elements 7 and 10 in absolute value becomes less than one of the reference voltages.

At each reduction of the transmission coefficient of the discrete divider 2 from the control block b, a signal is sent to a scale counter 9, the output of which receives the scale of the signal being converted.

After the input signal has been scaled by the signal from the control block b, the key 3 is closed and the signal from the discrete divider 2 is fed to the input of the comparison block 4. From this point on, the signal is converted by a bit-balancing algorithm into a digital code. At the device output, the group of information outputs of the control block b is combined with the group of outputs of the scale counter 9. Thus, at the output of the converter, there is a representation of the input signal in a digital position code, taking into account the scale.

Compared with the known device, the proposed analog-to-digital converter allows increasing the dynamic range of input signals while maintaining the accuracy of the signal representation in the digital code due to the fact that the input signal is compared to the dynamic range of the digital-to-analog converter before conversion and when it is exceeded, it decreases automatically. scale in the digital output code.

The use of an ADC with an extended dynamic range of input signals is advisable when generating arrays of data for computing computer characteristics of non-stationary random processes that are characterized by a large uncertainty of the dynamic range, as it will improve the accuracy of the representation of signals, avoid errors when i calculate x and lead to cost savings.

The use of the invention is advisable when building analog-to-digital converters, allowing you to work with signals with large

dynamic range, for example, when building an automatic device for inputting analog signals to a computer.

Claims (2)

Invention Formula An analog-to-digital converter containing an analog storage unit, the first input of which is connected to the first output of the control unit, the first group of control outputs of which is connected to the digital inputs of the digital-analogue converter, the first output of which is connected to the first input of the comparison unit, the output of which is connected to the first control unit input, a key, and an OR element, distinguished by the fact that, in order to expand the dynamic range of the input signals while maintaining the accuracy of the conversion, it additionally A discrete divider, the first and second threshold elements and a scale counter are entered, the second input of the analog storage unit is connected to the input bus, and the output is connected to the input of the discrete divider, the group of control inputs of which is connected to the second group of control outputs of the control unit, the second the output of which is connected to the first key input, the output of the cat & h is connected to the second input of the comparator unit, and the second input to the output of the discrete divider and the first inputs of the first and second threshold elements, the second input Which are connected respectively to the second and third outputs of the digital-analog converter, and the outputs of the first and second threshold elements are connected respectively to the first and second inputs of the element or; the output of which is connected to the second input of the control unit, the third output of which is connected to the input of the scale counter, the output group of which is combined with the main output of the information outputs of the control unit 0 and connected to the output bus. t Sources of information taken into account in the examination 1, Soucek B. Mini-computer systems 5 information processing, M., 1976, p.385. 2. USSR author's certificate number 805490, cl. H 03 K 13/17, 1979 (prototype).