SU1411970A2 - Device for determining characteristics of a-d converter - Google Patents

Abstract

The invention relates to computational and measuring tech- nique designed to automate the testing of analog-digital converters (ADCs), which include the detection of dynamic and static errors in ADCs, and can be used in information-measuring complexes, automated research systems, and the like. In order to increase the accuracy of determining the error of the ADC and increase the reliability of the static error characteristics, the device additionally introduces the required number of serially connected filter blocks of a certain structure that suppress the component errors of the ADC due to nonlinear distortions of the shape of the test sinusoidal signal. 1 hp f-ly, 2 ill. i (L

Description

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11411970

The invention relates to the field of computing and measuring equipment, is intended to automate the testing of the analog-digital converter (ADC), can be widely used in information measuring complexes, automated research systems and is an improvement of the device, according to the main author. No. 936419.

The purpose of the invention is to increase the reliability of estimates of static characteristics by increasing the accuracy of determining the error value.

Fig. 1 shows a block diagram of a device for determining the characteristics of an ADC; FIG. 2 is a block diagram of one filtering unit.

The device contains ADC 1, the element 20 Ki (k-l) ro pulse generator 7 2 digital delay, digital sum pulses,

torus 3, unit 4 for calculating static signal Y, after multiplying in characteristics, indicator 5, generator digital multiplier 12 by 6 coefficient of sinusoidal voltage, pulse generator 7, two frequency meters 8 25 and 9, first 10 and second 11 blocks of nonlinear function, two digital multipliers 12 and 13, the second element 14 Digital delay, k blocks 5k filter

signals f (J and fg, outputs a digital signal equal to

.2 owls ().

9

At the time of the generator 7 pulses k-ro pulse at the output of the ADC 1

10 a digital signal y appears. , Which is the value of the input analog signal at the time of generation of the k-ro sync pulse. The signal y is fed to the input of the adder 3, with the first

15 digital delay element 2, synchronized by the generator of 7 pulses, generates a signal y on the signal, which is the digital value of the input analog signal at the time of generation, 2 ffT I -2 cos (-5--)

H

enters the input of the adder 3,

In addition, at the considered time point at the output of the second eleration. Each filtering block of content 14 of a digital delay synchronized by the pulse generator 7. A signal is outputted. which is also fed to the input of the adder 3,

Thus, the adder 3 calculates the signal A, equal to the generator 6 of the sinusoidal voltage, two elements 16 and 17 of the digital delay, two blocks 18 and 19 of the nonlinear function, two digital multipliers 20 and 21, the digital adder 22,

y -2 cos (2 ™ -) y,., + y ,.

pulses and a pulse generator 7 have setting inputs, by means of which the frequencies of the generated signals and the amplitude of the sinusoid are set, the sinusoidal analog signal from the sinusoidal voltage generator 6 is fed to the working input AID I and the signal from the pulse generator 7 to the ADC synchronization input The ACCH1 1 clock converts the value of the analog signal currently present at its input into digital form.

At the same time, signals from pulse generators 7 and sinusoidal voltage b are fed to frequency meters B and 9, respectively, the outputs of which make digital signals, respectively, a and fJ, proportional to the frequencies of the signals entering their inputs. The first block 10 of the nonlinear function, to the input of which

0 Ki (k-l) ro pulse generator 7 pulses,

signals f (J and fg, outputs a digital signal equal to

.2 owls ().

9

At the time of the generator 7 pulses k-ro pulse at the output of the ADC 1

10 a digital signal y appears. , Which is the value of the input analog signal at the time of generation of the k-ro sync pulse. The signal y is fed to the input of the adder 3, with the first

5 digital delay element 2, synchronized by the pulse generator 7, outputs a signal y at the output, which is the digital value of the input analog signal at the moment of generation. After the signal in the digital multiplier 12 is multiplied by a factor

 , 2 ffT I -2 cos (-5--)

H

enters the input of the adder 3,

In addition, at the considered moment of time at the output of the second EleCo, the adder 3 tc signal A, equal to

y -2 cos (2 ™ -) y,., + y ,.

H

where u, uk-4

samples, t, e, are numerical values of the instantaneous values of the sine wave (coming from the generator 6 of sinusoidal voltage), obtained at the moments of the occurrence of responsibly (k-2) -ro (kl) -ro and k-ro pulses at the output of the generator 7 pulses ;

frequencies, respectively, of a sinusoidal signal and pulses. The second block 11 of the nonlinear function generates in digital form a signal equal to the reciprocal of the sum of the modules of coefficients for the samples in the last expression, i.e., equal to

f f (

1 / (2 2lcos () l). I

After multiplying the signal d from the output of the adder 3, by the signal from the output of the second block 11 of the nonlinear function performed by the digital multiplier 13, a value is obtained that characterizes the Q conversion error, converted to a single sample. We denote this value by P ,, n).

These reduced values are fed to the input of the first block 15.1 of the filter, the output of which produces the values reduced to one sample (we denote them by characterizing reliability of work, in which there is no component 2o of the adder 22 coming from the output,

The j-ro filtering units correspond to the moments of the occurrence of (k-2) -ro, (k-l) -ro and k-ro pulses at the output of the generator 7 pulses, respectively.

The second block 19 of the nonlinear function generates in digital form a signal equal to the reciprocal of the sum of the modules of coefficients for the values in the last expression, that is, a signal equal to

1 / (2.2 | owls (). I f

After multiplying the signal l

J

Due to the influence of the second harmonic in the spectrum of the test sinusoidal signal,

R. value

J (K

exit (J-1) -th

The filtering unit is fed to the input, j-ro of the filtering unit, and is fed to the input of the adder 22, while the digital delay element 16, synchronized by the pulse generator 7, outputs the signal P, -,.) which is the value of the signal at the input of the j-ro filtering unit at the time of generation of the (kl) th pulse by the generator of 7 pulses.

The first block 18 of the nonlinear function, the input of which receives digital signals fа and fJ. from the outputs of the frequency meters 8 and 9, respectively, outputs a digital signal equal to

-2 owls

.

(

after multiplying by which in digital multiplier 20, the signal Pj (((./ i) is fed to the input of adder 22,

In addition, at the considered moment of time, the output of the digital delay element 17, synchronized by the pulse generator 7, produces a signal P. ;, c ...) which is also fed to the input of the adder 22,

Thus, the adder 22 calculates the signal

 Jh

equal

W (qd)

+ (-2 cos (2 yfilk)) P ,, .. p.

%

/ (K-iT jdj)

- value of the input signal

coming from the output of the adder 22,

The j-ro of the filtering unit ции corresponding to the moments of occurrence of (k-2) -ro, (k-l) -ro and k-ro, respectively, of the pulses at the output of the pulse generator 7.

The second block 19 of the nonlinear function generates in digital form a signal equal to the reciprocal of the sum of the modules of coefficients for the values in the last expression, that is, a signal equal to

1 / (2.2 | owls (). I f

After multiplying the signal l

J

The signal from the output of the second block 19 of the nonlinear function, implemented by the digital multiplier 21, generates a value (we denote it

through P, -, (() characterizing the error in the operation of the ADC, in which there is no contribution of the (+1) -th harmonic of the sinusoidal signal spectrum at the output of the sinusoidal generator 6

tension

From the output of the filtering unit 15k, these values are fed to the unit 4 for calculating static characteristics, in which the estimates of the static characteristics of the error of the ADC are calculated. These characteristics are induced in display unit 5.

Claims (1)

Invention Formula 1, Device for determining the x-paKTepHCTHK analog-to-digital converter according to the author. No. 936419, characterized in that, in order to increase the reliability of static characteristics estimate, by increasing the accuracy of determining the error value, k serially connected filtering blocks are introduced, the first input of the first of which is connected to the output of the second digital multiplier, and the output of the last is connected to the input the unit for calculating statistical characteristics, the second inputs of the filtering units are combined and connected to the output of the pulse generator, the third and fourth inputs are respectively combined and connected to the output I will give the first and second frequency meters, respectively. 2 "Device pop, 1, distinguished by the fact that the filtering unit contains two blocks of a non-linear function, two digital multipliers, a digital adder and two digital delay elements, the first inputs of which are 6 times connected and are the second input of the filtering section, the first input of which is the second input of the first element of the digital delay and the first input of the digital adder, the second input of which through the first digital multiplier connects the hoist to the output of the second digital 0 the third delay element, the third input through the second digital delay element is connected to the output of the first. digital delay element, and the output is connected to the first input of the second digital multiplier, the output of which is the output of the filtering unit, and the second input is connected to the output of the first block of the nonlinear function whose input is combined with the second input of the first digital multiplier and connected to the output of the second block nonlinear function, the first and second inputs of which are respectively the third and fourth inputs of the filtering unit. Phys. 1 Fie.2