SU1229824A1 - Device for measuring aperture uncertainty of analog-to-digital converter - Google Patents

Abstract

The invention relates to a measurement technique and makes it possible to increase the measurement accuracy of the aperture uncertainty of parallel analog-to-digital converters (ADC). The proposed device measures the frequency of the code at the output of the ADC under investigation with the code corresponding to the level of the input voltage of the ADC at which the aperture uncertainty is measured. For this, using a delay element, a strobe pulse is applied at the control input of the ADC at the time point at which the voltage of the linearly rising edge of the pulse entering the ADC input from the generator output, pulses, is slightly less than the required measurement level. Then, the voltage at the output of the digital-to-analog converter is increased in steps of one quantum. At each step, the amplifiers of the studied ADC are supplied with small increments of the reference voltage to the inputs of the comparators of the studied ADC, which leads to an exact shift of the comparators' response times. By measuring at each step the frequency of coincidence of codes at the output of the ADC with the specified one. The code determines the function of the distribution of the aperture uncertainty of the ADC. 1 silt V

Description

The invention relates to a measuring technique and can be used to determine the aperture; uncertainties of high-speed parallel analog-digital converters (ADC) „

The aim of the invention is to improve the accuracy of the device for measuring the aperture uncertainty of analog-to-digital converters.

The drawing shows a block diagram of the device.

The device contains the studied | 1 CRT 1, a generator of 2 pulses, an element 15 delay 3, a driver 4 pulses, a digital-to-analog converter 5, a reference voltage source 6, a differential amplifier 7, an inverting amplifier 8 and a comparison unit 20.

The device works as follows.

The measurement of the aperture uncertainty of the ADC is carried out in two stages. At the first stage, the input voltage of the ADC 1 under investigation is set, at which it is necessary to measure its aperture uncertainty. JQ To do this, a zero code is fed to the input of the D / A converter 5, a code to the second input of the block 9, corresponding to the required input voltage level of the A / D converter 1 o Then, at the control input of the delay element 3, the value of the code starts to increase sequentially, thereby increasing the arrival delay pulse to the gate input of the ADC 1 on. relative to the beginning of the linearly rising edge of the pulse supplied to the information input of the ADC 1 from the output of the generator 2 pulses. The delay of the arrival of a strobing pulse is increased by one quantum at fixed intervals until at least one operation of the comparison block 9 occurs in a given time interval. For a fixed interval duration that is significantly longer than the pulse duration at the generator 2 output, the voltage information input of the investigated ADC 1 is close, but less than the required level. quantization of the ADC, at which it is necessary to measure its aperture uncertainty.

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At the second stage, the measurement of the aperture uncertainty of the A / D converter is carried out. Since the aperture uncertainty is a random function, it is necessary to conduct a series of tests under its measurement under the same measurement conditions. In the proposed device, the frequency of the codes at the output of the A / D converter 1 with the given code is measured depending on the voltage level at the output of the digital-to-analog converter 5. For this, the voltage at the output of the digital-a is. The signal converter 5 is increased from the zero level set at the correction stage in steps of one quantum and the frequency of the codes at each step, for example, is measured by counting the number of code matches in a fixed time interval.

In addition, at each step of measurement

With the help of amplifiers 7 and 8, small increments of the reference voltage are applied to the inputs of the comparators of the ADC 1 under study, which leads to an exact shift of the response times of these comparators.

According to the measurement results, the differential or integral function of the distribution of the aperture uncertainty of the ADC under study is determined.

Thus, by feeding the inputs of the comparators of the ADC 1 under study to small increments of the reference voltage in the proposed device, it is possible to make an exact time shift of the response times of these comparators and thereby increase the measurement accuracy of the aperture uncertainty of the parallel ADC.

Claims (1)

Invention Formula A device for measuring the aperture uncertainty of analog-to-digital converters, which contains a digital-to-analog converter, whose input is the first input of the device, a delay element, the control input of which is the second input of the device, a pulse generator, the output of which is connected to the input of the delay element, which output is connected to the input of the pulse shaper, the output of which is connected to the gate input of the analog-digital converter under study, the output of which is connected to the first input of the bl Single comparison, the output of which is the output of the device, and the second input is the third input of the device, the source of the reference voltage, characterized in that, in order to improve the accuracy of the device, noninversion and differential amplifiers are introduced, the outputs of which are connected respectively to the first and second control inputs The analog-digital converter under study, the information input of which is connected to the output of the pulse generator, inverts the 1st input of the differential amplifier connected to the voltage source, and the non-inverting input - to the output of the digital-anode converter and the input of the non-inverting amplifier. Output Editor L.Gratillo Order 2454/52 Compiled by N.Dikarev Tehred I.Popovich Proofreader I.Musk Circulation 543 Subscription VNIIPI State State Committee of the USSR for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4