SU1718380A1 - Adc tester - Google Patents

Abstract

The invention relates to analog-digital and information-measuring technology. The device can be used to test and adjust samples of analog-to-digital converters (ADC) in the manufacture, as well as in the input and output control, by manufacturers and consumers of the ADC. The purpose of the invention is improving the accuracy and widening the scope The input of the controlled ADC 16 from the output of the adder 4 is supplied with a voltage of a complex shape, which is the sum of a constant variable across the bus 15 component formed at the output of the voltage source 3 and a low frequency variable (symmetrical sawtooth shape) formed at the output Oscillator 1. From the generator of 6 clock pulses, sync pulses are received at the ADC 16. The code output signals of the various bits of the A / D converter 16 are sequentially (or selectively) passed through the switch 10 to the input of the filter 9, the time constant of which is small for the code signal and large for noise. The output signal of the filter is fed to the vertical input of the recorder 2, on. the horizontal input of which is supplied with a sawtooth signal from the first output of GUI 1. 3 Il.

Description

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The invention relates to analog-to-digital and information-measuring equipment and can be used to examine samples of analog-to-digital converters (ADC) in the manufacture, as well as at the output and input control, by manufacturers and consumers of the ADC.

The purpose of the invention is to improve the accuracy and the expansion of the scope,

FIG. 1 shows a functional diagram of the proposed device; FIG. 2 is a graph of the output signal of the filter on the recorder screen; in fig. 3 is a diagram of the filter and sawtooth generator.

The proposed device comprises a sawtooth voltage generator 1 (GPN), a recorder 2, a voltage source 3 (IN), an adder 4, a device output bus 5, a generator of 6 clock pulses, a device output bus 7, a divider 8, a filter 9 and a switch 10 , control bus 11, input bus 12, control buses 13-15.

The device works as follows.

The ADC under study 16 is connected by an analog signal input 7 to the output bus 5 of the device, and the clock input is connected to the output bus 7 of the device. The code outputs of the ADC 16 are connected to the input bus 12 of the device.

Control and measurement of noise (variance o) ADC 16 is carried out using an image on the screen or a register 2 schedule, depending on whether the instrument used as a recorder is an oscilloscope or a recorder (hereafter we assume that an oscilloscope is used).

The measured value is determined from

Formulas a - - --- z--, where Uo.9 and Uo.1 - To

The input voltage of the ADC, at which the output digital signal of the ADC 16, averaged by filter 9, is at levels of 0.9 and 0.1 of its maximum value (Fig. 2c).

. The input of the controlled ADC 16 from the output of the adder 4 is supplied with a voltage of a complex shape, which is the sum of a constant variable at the input 15 of the component formed at the output of the source. The voltage of the low-frequency variable component (symmetrical sawtooth) formed on output GPN 1. With the generator 6 clock pulses (GTI) at the ADC 16 receive clock pulses.

The code output signals of the various bits of the A / D converter 16 are sequentially (or selectively) passed through the switch 10 to the input of the filter 9, the time constant of which is small for the code signal and large for noise. The output signal of the filter is fed to the vertical intelligence input of the recorder 2, to the input of the horizontal scan of which a sawtooth signal is supplied

first output gpn 1.

Transducer code outputs are pulse sequences with different frequencies. In the absence of noise in the ADC 16 transitions from

one code to another occurs at certain values of the input signals of the converter 16 (Fig. 2a).

In the presence of noise in the ADC 16, the code signals are noisy (Fig. 2 b). After filtering, the signal is a smooth curve (Fig. 2c). In order to ensure that the time of the filter 9 does not introduce an additional error, its value is controlled by the bus 14 simultaneously with the change in the frequency of the FPN1.

On the oscilloscope screen it is easy to determine the levels Wo, 9 and Uo.1, since all the screens are equipped with the corresponding marks, and to calculate the value a.

If there is one main component in the noise spectrum (when generated in ADC 16), the appearance of the smooth curve is distorted (kinks, humps, shelves, etc.) appear, as shown in FIG. 2g. This makes it possible to use a device for detection of generation in the A / D converter 16, which greatly extends its functionality.

Thus, using the proposed device, you can control

the amount of noise and the presence of generation for any value of the output code of the ADC 16.

FORMULA AND A C A B R E N T E Analog-digital control device

converters, containing a sawtooth generator, the first output of which is connected to the first input of the voltage source recorder, the output of which is connected to the first input of the adder,

the second input of which is connected via a voltage divider to the second output of the sawtooth generator, and the output is the first output bus of the device, the second output bus of which is the output of the clock generator, and the input bus is the information inputs of the switch, the control input of which is the first control bus, the second and the third control bus are respectively the control input of the voltage divider and the input of the voltage source, characterized in that, in order to improve the accuracy and application, introduced a filter having an information input coupled to an output commutator

the torus, the output is with the second input of the recorder, and the control input is combined with the control input of the sawtooth generator and is the fourth control bus.

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Claims (1)

Claim A control device for analog-to-digital converters containing a sawtooth voltage generator, the first output of which is connected to the first input of the voltage source recorder, the output of which is connected to the first input of the adder, the second input of which is connected to the second output of the sawtooth voltage generator through the voltage divider, and the output is the first output the device bus, the second output bus of which is the output of the clock generator, and the input bus is the information inputs of the switch, I control whose input is the first control bus, the second and third control bus are respectively the control input of the voltage divider and the input of the voltage source, characterized in that, in order to increase accuracy and expand the scope, a filter is introduced, the information input of which is connected to the output of the commutator - 5 tori, the output is with the second input of the recorder, and the control input is combined with the control input of the sawtooth generator and is the fourth control bus. -h