SU1757100A2 - Device for control of digitizers - Google Patents

Abstract

The invention relates to analog-digital and information-measuring technology. The device can be used for research and adjustment of samples of analog-digital converters in the manufacture, as well as at the output and input control manufacturers and consumers of the ADC. The clock input 25 of the investigated ADC 23, connected to the input of the counter 9, receives pulses from the output of the generator 13 clock pulses. The analog input 24 of the A / D converter 17 is supplied with a signal of the adder b, the first input of which is supplied with a constant voltage from the output of the voltage divider 8. The input of the voltage divider 8 is received from the first output of the sawtooth generator 3, from the second output of which the signal is fed to the input U (vertical scan) of the oscilloscope 4.. The output parallel code is converted by

Description

 with

Xi

oh oh

Phie.1

Yu

of the output signal of counter 9 on converter 1 of a code into a serial code, the beginning of which in synchronizer 11 is aligned with the start of the signal from the trigger generator 10, the input from the output of counter 9 pulses the signal from the first output of the synchronizer and triggers a horizontal oscilloscope signal The second output of the synchronizer 11 is amplified in the generator of the 12 voltages and is fed to the input Z of the oscilloscope's illumination. 4 The invention relates to an analog-to-digital and information-measuring Noah engineering and power upgrading device for avto si №1631725

The device can be used for research and adjustment of analog-to-digital conversion samples (LCP) in the manufacture, as well as at the output and input control by manufacturers and consumers of LCP

A device for monitoring analogue digital converters containing a parallel code-to-serial converter is known, the first inputs are expensive, the first inputs are devices, a sawtooth generator, the first output of which is connected to the first input of the oscilloscope, the voltage source whose output is connected to the first input of the summer, the output of which is the first output of the device, a voltage divider, a counter, a start pulse shaper, a synchronizer, a voltage converter, and a clock generator x; pulses, the output of which is connected to the second output of the device, the first synchronizer input and the counter input, the outputs of which are connected to the second inputs of the parallel code to serial converter and the inputs of the trigger pulse generator, the output of which is connected to the second synchronizer input, the third input of which is connected to the output of the parallel code converter and a serial one, the first output to the second input of the oscilloscope, the second output of the sawtooth generator is connected to the first input of the divider voltage, the second input of which is the second input device and an output connected to the second ahodu adder, a third input roist mouth to a source connected to the input voltage.

The oscilloscope 4 screen is a raster image, which simultaneously contains information about the resolution of the ADC with several adjacent code combinations, hooks and the values of these combinations. Separate check bit generated on the oscilloscope screen A using the 0 scaling unit , the comparator 17, the switch 18 and the multiplexer 19, will constantly control the performance of the device 2

The disadvantage of the known device ppcc is low due to the lack of a signal about the operability of the device itself, those. when getting out

the investigated ADC signals that do not match the correct ones, the question arises about the health of the control device itself (for example, the absence of failures in the digital node, as well as the level of intrinsic noise

devices)

The aim of the invention is to increase the reliability and accuracy of

A similar goal is achieved by introducing a comparator into the device, switching

a torus, a multiplexer and a scaling unit, the input of which is connected to the output of the voltage source, and the output of the first input of the comparator whose second input is common, the output of the comparator is connected to the information input of the switch, the first outputs of which are connected to the corresponding first information inputs of the multiplexer whose second informational inputs are

They have corresponding first inputs and inputs, the multiplexer outputs are connected to the corresponding first inputs of a parallel code converter to a serial one, the third input of which is connected to the second input of the switch, the control inputs of which are the corresponding bulleted input shich, the control input of the multiplexer is n that input bus

On fmg 1 shows the functional diagram of the proposed device; Fig. 2 is a shadow image of the output current of the ADC and the check bit on the oscilloscope screen, illustrating the principle

imaging using light intensity modulation

The control device of the analog-to-digital converter contains a parallel code to serial (PC) converter 1, inputs 2 are the first inputs of the device, a sawtooth voltage generator 3, an oscilloscope 4, a voltage source 5, an adder b, the output of which is the first output 7 of the device , voltage divider 8, counter 9, start pulse shaper 10, synchronizer 11, voltage converter 12, and clock generator 13, the output of which is connected to the second output 14 of the device, to the first synchronization input the congestion 11 and the input of the counter 9.

The outputs of the counter 9 are connected to the second inputs of the converter 10 start pulse, the output of which is connected to the second input of the synchronizer 11, the Third input of the synchronizer 11 is connected to the output of the converter 1 of the parallel code to the serial. The first output of the synchronizer 11 is connected to the second input of the oscilloscope 4, and the second output through the voltage converter 12 to the third input of the oscilloscope. The first output of the sawtooth generator is connected to the first input of the oscilloscope 4, the second to the first input of the voltage divider 8, the Second input of the voltage divider is the second input of the device 15, and the output of the voltage dividers 8 is connected to the second input of the adder 6. The third input The device 16 is connected to the input of a source of 5 voltages. The output of the comparator 17 is connected to the information input of the switch 18, the outputs of which are connected to the first information inputs of the multiplexer 19, the second inputs of which are the corresponding first input buses 2 of the device, and the outputs are connected to the first inputs of the parallel-to-code converter 1. The third input of the inverter 1 is connected to the second output of the switch 18.

The input of the scaling unit 20 is connected to the output of the voltage source, and the output via the comparator 17 to the input of the switch 18. The control inputs of the switch 18 and the multiplexer 19 are the fourth 1 and fifth 22 device inputs, respectively.

The device works as follows

The ADC 23 under study is connected via the input bus 24 of the analog signal to the output bus 7 of the device, and via the input bus 25 clock pulses to the output bus 14 of the device. The output code buses 26 of the ADC 23 are connected to the input buses 2 of the device.

The proposed device operates in two modes: Operation and Monitoring.

In the Signal operation mode from bus 22, multiplexer 13 connects the inputs 2 5 of the device to the inputs of the converter 1 of parallel code to serial.

Control and measurement of parameters (resolution and differential nonlinearity) of the ADC 23 is carried out

0 on the oscilloscope screen 4. On the oscilloscope 4, using a special sweep and modulation of the beam brightness, a raster image is created in which simultaneously the co5 holds information as the resolution of the ADC 23 with several neighboring code combinations and values these combinations. The measured value (resolution) is displayed

0 is geometrically - the height of a certain element of the image, which facilitates the comparison of neighboring elements when determining the differential nonlinearity. The input of the controlled ADC 23 from the output of the analog adder 6 is supplied with a voltage of a complex form, which is the sum of a constant regulated component formed at the output of the source 2 of the voltage (IN) and a low-frequency variable component (symmetrical sawtooth) formed at the output of the generator 3 sawtooth voltage (GPN). The magnitude of the sawtooth voltage at the input of the analog adder b is determined by the division factor of the voltage divider 8. The repetition frequency of the converter's cycles (i.e., the input signal's conversion frequency), set using a 13-clock pulse generator, exceeds the frequency of the sawtooth voltage at the output of the HPF 3 many times, therefore, during any one conversion cycle, the input voltage The ADC has almost no time to change significantly. The code from the output of the A / D converter 23 corresponding to this voltage is serialized (Fig. 2a) in the T code converter, and then after binding to the synchronizer 11, it is output to the oscilloscope 4 screen via the third input (channel 2

The sweep of the oscilloscope 4 runs simultaneously with the beginning of the issuance of a sequential code, for which in the driver 10

5 of the signals of counter 9, a trigger pulse is generated, the leading edge of which, before arriving at the synchronization input of the oscilloscope 4, is aligned in the synchronizer 11c with the leading edge of the first bit of the serial code.

The sequential code received at the input Z modulates the brightness of the beam as it moves along the horizontal scanning line, so any code combination is displayed by a combination of light and dark segments of the horizontal line. These lines periodically move vertically under the action of a sawtooth voltage supplied from the output of the FPG 3 to the first input Y of the oscilloscope 4. Since the vertical movements of the scanning lines are made simultaneously with the change in the input voltage of the ADC 17, which causes a corresponding code change at the outputs of the ADC 26 23, PC 1 and PN 12, a raster image is obtained on the screen of the oscilloscope 4, showing the relationship between the input voltage and the code at the output of the ADC 17 (Fig. 2b).

If the ratio of the horizontal scanning frequencies and the sawtooth voltage is sufficiently large, the individual raster lines merge and cease to differ. The resulting image can be represented as consisting of a series of horizontal stripes displaying a series of code combinations. The height of a band is proportional to the quantization step corresponding to the displayed combination, i.e. The strip height geometrically displays the resolution of the ADC 23 with a certain code at the output. The number of bands simultaneously observed on the screen depends on the range of the sawtooth component at the input of the A / D converter 22 and can be selected by anyone (at the discretion of the operator) by changing the voltage ratio of the voltage divider 8, sending the appropriate signal through the bus 15. When the resolution value changes the number of lanes is usually chosen to be no more than 6. In any case, the order of displaying the individual code bits remains unchanged, therefore columns can be distinguished in the image that correspond to Sponsored and retained their location for any changes in the input voltage of the ADC 23.

The image shown in FIG. 26 corresponds to only a small portion of the static characteristic. The ability to control any sections of the characteristic is ensured by continuously adjusting the constant component of the input voltage of the ADC 23.

To adjust the DC component, the operator delivers a control signal on bus 16 that changes the signal of voltage source 5 to the desired voltage range. Search for a required plot ha;

The characteristics of the ADC 23 are facilitated by that. that the image is a characteristic pattern of rectangles, the pattern of construction of which is detected

it is quite simple, as well as the fact that the size of the displayed area is also regulated by the operator. Any violations of the pattern construction pattern caused by non-linearity of the characteristic are easily

are marked by the operator and for their detection it is not necessary to refer to the table or make calculations.

Connecting the second output of the switch 18 to the second output of the converter

parallel code in the serial allows you to create an additional control section, which, along with the bits of the ADC 23, the passage through the blocks 1, 11, 12, is displayed on the screen of the oscilloscope 4. The check bit differs from the others in that it has a constant view on the screen (leftmost in FIG. 26), namely due to the fact that a sawtooth voltage does not reach the first input of the comparator, but

The second input is permanently connected to 0V. Depending on the scaling factor of the block 20, the light-shadow transition level in the test bit may be different (Fig. 2 shows the case of K20 KG, i.e. when

The conversion coefficients of the output voltage of block 5 in blocks 20 and 6 are the same, the light-shadow transition in the test bit occurs in the middle of the oscilloscope screen). Since the formation of the additional bit involves all units of the device except two (divider 8 voltage of adder b and partially converter 1), the presence of additional bit on the oscilloscope screen makes it possible with a certain probability to judge the health of the device as a whole.

In the control mode, the signal from the bus 22, the multiplexer 13 connects the outputs of the switch 18 to the converter inputs

1, and the signals from the bus 21 provide the output of the comparator 17 through the switch 18 and the multiplexer 19 in series to all the first inputs of the converter 1. This operation allows you to sequentially view the device's performance through all the inputs of the converter 1.

In addition, since the noise characteristics of the comparator 17 are known, noise (characterized by the width of the transition zone

light-shade) in an additional bit can serve as a standard for determining the noise of the proposed device, which makes it possible to determine the noise of the ADC 23 by the formula

AUAUni L 1GATSP1 - (A Okr - A UK),

where L УАЦП - required noise voltage in bits of ВЦП 23;

Lee Dzgl - noise voltage measured on the oscilloscope 4 screen in the ADC 23 bits;

D 1) cr - noise voltage in the test discharge;

AIJK is the reference (or specially measured) noise voltage of the comparator 17.

The noise voltage Lidzsch determined by formula 1 is a more accurate characteristic of ADC 23 than the measured Aidp used in a known device,

The use of the invention will improve the accuracy of measuring the noise of the ADC and the accuracy obtained by using the information device will serve to quickly determine the moment of failure of the device.

Claims (1)

Invention Formula Control device for analog-digital converters according to the model, № 1631725, but) "GgtiTO cq" Schei-WW PЪ аУат . // Ґ0 S 8 7 S S 3 g / O Raz L / xatfcf - Swxve / ft / e K w e g 7 6 & 4 $ 2 characterized in that, in order to increase accuracy and reliability, a comparator, a switch, a multiplexer and a scaling unit, an input are introduced into it which is connected to the output of the voltage source, and the output to the first input of the comparator, the second input of which is a common bus, the output of the comparator is connected to the information input switch, the first outputs of which are connected to the corresponding first information in the multiplexer moves, the second information inputs of which are the corresponding the first input buses, the multiplexer outputs are connected to the corresponding first inputs of the parallel code to serial converter, the third input of which is connected to the second output the switch, the control inputs of which are the corresponding fourth input bus, the control input of the multiplexer is the fifth input bus. -Swxve / ft / e Mr Wftwfrtf / ////////// 7/////// 27 / ; ////////// QfMffffOtf QtfffffffOfO QfWMfOOj