SU738151A1 - Device for measuring analogue- digital converter dynamic characteristics - Google Patents

Description

(54) DEVICE FOR;: MEASUREMENT OF DYNAMIC CHARACTERISTICS OF ANALOG-DIGITAL

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The invention relates to a digital electrical measuring technique and is designed to measure the error characteristics of analog-to-digital converters (ADC) over time.

To estimate the error introduced by the ADC when encoding wideband random or deterministic signals, it is necessary to know the conversion error in the dynamic mode, its maximum or root mean square value depending on the distribution law, the frequency spectrum and the correlation function of the input signal.

It is known device dL calibration of the ADC in the dynamics. It contains an analog generator of an exemplary sinusoidal signal, a calibrated A / D converter, a control unit, an exemplary instrument for measuring the actual value of the input sinusoidal signal, a selective amplifier, a phase shifter, indicator devices, a low-frequency driver, a CONVERTER cascade

incidence ratios, frequency multiplier at dispersed time points G.

This device has a complex structure and low speed:; tvie, since all the basic operations for phasing the exemplary signal and control | pulses are carried out manually, which is very time consuming and very difficult,

It is also known device Cham © 10 Renee dynamic; characteristics of the ADC, contains a verifiable ADC, a pseudo-random 1X level values sensor, a level register, a digital-to-analog level converter; pseudo-random sensor

G5 values of speeds, reversible counter, analog converter of speeds, analog yummator, digital controlled multivibrator, ktoch, output code storage register, block

iO processing, the first and second subtraction blocks, the pulse generator, the control block, the time delay block, and the logic p1d delay OR or 2}. In this device, the measurement of the dynamic characteristics of analog-to-digital converters is more universal, it is fully automated and allows you to measure the dynamic errors of the ADC under the influence of pseudo-random input signals with a given distribution law and a given autocorrelation function .... The main disadvantage of this device is that the measurement of the error of the ADC in the dynamics is carried out on a pseudo-tea-input signal with given distortion laws and an autocorrelation function, and this does not allow us to estimate the dynamic error. The ADC when encoding wideband random or deterministic signals and determining, for example, its maximum and root mean square value, is a scientific research institute depending on the distribution law and the type of correlation function. , input signal. The purpose of the invention is to expand the functionality when measuring the dynamic error of analog-to-digital converters when coding randomly with any distribution law. The goal is achieved by the fact that the device containing a pulse generator, the input of which is connected to the start bus, and the output is connected to the input of the control unit and the input of the analog-digital converter, time delay unit, the first digital-to-analog converter, the output of which is connected with the first input of the analog adder, the second input of the last is connected to the output of the second digital-to-Logo transducer and to the input of the analog recorder of measurement results the input of the second digital-to-analog converter connected to the r.d) with a reversible counter and with the input of a digital indicator, two are added to compare the device, an analog subtractor, a logic unit and an exemplary random signal generator whose output is connected to the measuring input of the analog-digital converter and the first inputs compare 1, the second inputs of which are connected to the outputs of the analog adder and analogue switch, respectively, the outputs /: of the leveling devices are connected, respectively, with the first and second inputs of the Mir the third block is connected to the output of the control unit, the first output of the logic block is connected to the add-on bus, and the second to the readout bus of the reversible counter, whose signal input is connected to the first output of the analog-digital converter through the time delay block the first digital-to-analog converter, information. The input of which is connected to the output of the analog-to-digital converter, and the analog output is connected to the first input of the analog subtractor, the second input of the latter is connected to the output of the second digital-to-analog converter. The drawing shows a block diagram of the proposed device. It contains the generator 1 of the model random signal with the specified parameters, the test analog-digital converter 2, the first digital-analog converter 3, comparing devices 4 and 5, analog adder 6 and subtractor 7, block 8 time delays, generator 9 pulses, block , 10 controls, a logic unit 11, a reversible counter 12, a second digital-to-analog converter 13, a digital indicator 14, and an analog recorder 15 of measurement results. v .-. h The device operates as follows ...... The pulse generator 9 outputs to the control unit 10 and the A / D converter 2 clock pulses, according to which the subject A / D converter 2 converts a random signal) - generated by the generator 1, into a digital equivalent. At the end of each analog-digital conversion cycle, the time signal Uj (, Ct ) from ADC 2 according to the signal — the end of the conversion at time –fc, the inverse conversion of the digital equivalent Np (, –t,) to the voltage HHUUn5k (in,) occurs using the first digital-to-analog converter 3. This is the voltage Uj. ( -t tn) is summed to analog an adder 6 and is subtracted in an analog subtractor 7 with an additional voltage Uo Kii% which comes from a second digital-to-analog converter 13 controlled by a reversible counter 12. The following devices produce a comparison device 4 and 5 via logic unit 11 by the signal X, operations in the reversible counter 12. If the conditions for comparing devices 4 and 5 are correspondingly x (4. ((.. Чu, (t),), Te.V-i or under the conditions. Ux (-t .-. (Tj.a .. J ,,. ReX, which for both comparing devices corresponds to the expression (t, .t / iUn (-b, (V -vtn1-Un (the current analog-to-digital conversion error the input signal, a pulse from the output 2 of the pickup unit 11 is added to the reversible counter 12 and the voltage of the small-to-variable code-to-voltage converter 13 is increased by one quantum. Under the conditions for comparing devices 4 and 5, respectively: Ux (.. JxftKi -tn JV & UoCtj. ,, lixe.V that for both comparing devices corresponds to the expression l nx 4 -tnM l lJoC Ki-.b by a pulse from the output Z, logy: The unit and the voltage in the digital digital converter are subtracted by one quantum in the reverse counter 12. When measuring the root-mean-square value, the error AUnv of the ADC logic unit 11 is open to signals from the comparison control device Y with the control signal Y from the control unit Yu. In this case, in the process of reusable conversion cycles at the output of the second digital-to-analog converter 13, regardless of the initial state. sets the voltage Uo) which in the mean-static will be equal to the conversion error,. This state corresponds to the equality of probabilities .. L n L L% P-P 1 and ,, 1 1 dio1. When measuring modulo the maximum values of the error A.U (, fy, oi, junction counter 12 operates addition, starting from the zero initial state, and logic unit 11 is open for signals from equalization devices 4 and 5 by the control signal from unit 10 of the control unit

Claims (2)

1. USSR author's certificate No. 223475, cl. H 03 K 13/02, 1966. 2. USSR author's certificate according to application number 2467303/21 (prototype).