SU790289A1 - Analogue-digital converter monitoring device - Google Patents

Description

one

The invention relates to computing and can be used to control analog-to-digital converters. (ADC) used in communication systems with pulse-code 5 modulation.

A device is known in which an electronic digital computer (ECM) is used for monitoring. The ECM generates a digital-10 signal that is subjected to analog-to-digital conversion. The digital signal from the controlled output. The ADC is fed to the digital computer, where, as a result of its comparison with the original digital 15 signal, the parameters of the controlled ADC are calculated. Such a device makes it possible to estimate the contribution of each bit of the ADC JF3 controlled parameter ADC AND,

However, the effect of the non-ideal operation of the digital-analog converter (DAC) on the results of the calculations is preserved: in the monitoring process, the ADC function is interrupted in the system.25

A device for monitoring an analog-to-digital image signal converter is known, in which a sawtooth voltage is applied to the input of a controlled ADC. This device is known as 30

It is necessary to exclude a D / A converter from an ADC control circuit and evaluate the contribution of each bit to the distortion arising during the analog-digital conversion. Element I is connected to the outputs of the ADB bits, the second inputs of which are connected to the outputs of the shift register, one of the inputs of which is connected through series the first delay line and the first differentiating circuit are connected to the OUTPUT of the generator of half-frame sync pulses, which is also connected to the Ban element, the second input of which is through the second differentiating circuit and the frequency divider You are connected to the output of the horizontal sync pulse generator through the second delay line, and the output of the Inhibit element is connected to the inputs of the shift register, and the outputs of the AND elements are connected via the OR element to the indicator input. used video control device. Thus, the signals from the outputs of the ADC bits are alternately connected to a video monitor, on the screen of which an image of code table 2 is formed. A disadvantage of the device is the impossibility of detecting dynamic errors that occur in the ADC during the conversion of a random information signal, since the control It is produced only when transforming deterministic test signals, I Thus, the known device has limited functional capabilities and does not provide you with low confidence control. As a result, the known device does not provide continuous control of the ADC without interrupting its operation in the system. The purpose of the invention is to expand the functional capabilities and increase the reliability of the control. The goal is achieved by connecting an analog digital converter to the control device, the first input of which is connected to the input bus through the preliminary Testing of an analog signal and the second input of the analog preliminary testing and output clock generator containing elements AND, OR element, pulse distributor, sawtooth driver, and splitter The first inputs of the I and I terminals are connected to the outputs of the analog-to-digital converter, the second inputs are connected to the outputs of the pulse distributor, and the outputs through the OR element are connected to the indicator ray intensity modulation input, the matching unit is input, the matching unit connects to the input of the channel of the vertical deviation of the indicator, the input of the channel of the horizontal deviation of which through the sawtooth driver is connected in parallel with the joint p spredelitel pulses, and via a frequency divider - a clock generator output. The essence of the invention is to expand: the functionality and reliability of the control by forming the code table on the screen of the image indicator when the controlled ADC is applied to the course of both special test signals and a random information signal. The drawing shows a block diagram of the control device analogue of the digital converter. 1 "1 input signal through the analog signal pre-test unit 2 is connected to the input of the analog-digital converter 3, the second input of which is connected to the second input of the preliminary signaling unit of the analog signal 2 and the output of the sync pulse generator 4 Output of the sync pulse generator 4 is connected via frequency divider 5 with the input of the distributor 6 pulses and through the driver 7 of the sawtooth voltage - with the input of the channel of the horizontal deviation of the indicator 8. The outputs of the ADC 3 and distribute the impulse in connected with the corresponding inputs of elements AND 9. The outputs of elements AND 9 through the element OR 10 are connected to the modulation input of the beam intensity of the indicator 8. The output of the pre-test block of the analog signal 2 through the matching block 11 is connected to the input of the vertical deviation channel of the indicator 8. To the input of the block pre-test the analog signal 2 is supplied with the information analog signal from the input bus 1. In the block pre-test the analog signal 2, the analog signal is sampled into time (sampling) and storing the signal values, thereby preventing the signal from changing during the A / D conversion and A / D conversion. The sync pulses with a sampling frequency are supplied from the output of the generator 4 of sync pulses to the second inputs of the unit for preliminary testing of the analog signal 2 and the analog-digital converter 3, as well as to the input of the frequency divider 5. The tested information signal from the output of the preliminary testing unit of the analog signal 2 is fed to the first input of the analog-digital converter 3 and, through the matching unit 11 to the input of the vertical deflection of the indicator 8. The code pulses from the outputs of the analog-digital converter 3 through the elements And 9 ,,. 9, 9 are alternately fed to the input of the element OR 10. The time intervals during which the output of each bit of the ADC 3 is connected to the input of the element OR 10 are set by the distributor b pulses, the signals from the outputs of which are fed to the second inputs of the elements. AND 9, 9 ,, 9j. The pulses from the output of the frequency divider 5 are fed to the input of the distributor 6 pulses and the driver 7 sawtooth voltage. The output signal from the driver 7 of the sawtooth voltage is applied to the input of the horizontal deflection channel. the indicator 8, to which the modulation input of the beam of the beam receives code pulses from the output of the element OR 10. Thus, during the horizontal scanning period of the indicator 8, signals from the outputs of the ADC bits to the modulation input of the indicator beam 8 are alternately connected the time intervals corresponding to the pulses of the tested information signal in accordance with the code with which the converter operates, results in the appearance of an image of the code table on the indicator 8 on the screen. The signal provides the isolation of the output of the pre-test block of the analog signal 2, the indicator input 8 and the correct I time relations, i.e. the coincidence of the flat tip of the tested information signal on the vertical deflecting plates of the indicator 8 with the corresponding code pulses at the input of the brightness of the indicator 8 beam .

This device provides an extension of the control functionality of the ADC, which, thanks to the newly introduced element and connections, is produced not only in the process of transforming the deterministic test, but also random information signals. This ensures continuous control of the ADC without interrupting its functioning in the system, which leads to an increase in the technical and economic indicators of the system as a whole.

The device provides an increase in the reliability of the control, since control only from test signals does not allow detection of the dynamic errors in the complex arising in the ADC. In the process of converting a random information signal.

Thus, this device allows to control the correctness of the order of the code groups and unstable operation areas of the bits of the tested ADC without disturbing the functioning of the ADC in the current system.

Claims (2)

1. The patent of England W 1259614, 5 cl. G 4 H, 1972. 2. USSR author's certificate number 434619, cl. H 04 N 7/02, 1974 ((prototype).