SU920545A1 - Device for checking digital cell operation - Google Patents

Description

one

The invention relates to electrical measuring equipment and is intended for use in the calibration and adjustment of various boards and blocks of digital computers.

A known probe for monitoring the logic block circuits, containing input signal converters, the outputs of which are connected to the inputs of the open source decoder, a trigger, whose inputs are connected to the outputs of one of the input converters and the decoder, indicators, inputs are connected to the trigger and decoder outputs

A disadvantage of the known device lies in its narrow functionality. This probe does not allow detecting constant and pulsed signals with an overestimated level of logic O and-whether with an underestimated limit of logical 1, as well as signal drops from the level of logical O to the level of logical 1 or vice versa.

Closest to the invention is a device for controlling the operation of digital cells, containing three indicators, three threshold elements, two of which are installed at the input of the device and connected to the outputs of the first and second indicators, a pulse shaper,

10, the output of which is connected to the input of the third indicator, and the input to the output of the third threshold element connected to the inputs with the outputs of the first and second threshold elements 2.

15

Claims (2)

The disadvantage of this device is also determined by the limited functionality, since this device does not allow detecting pulse signals with an overestimated level of logic O and an underestimated level of logic 1. The purpose of the invention is to expand the functionality of the measuring device. The goal is achieved by the fact that a device for controlling the operation of digital cells, containing three indicators, two threshold elements, the inputs of which are connected to the input of the device, and the outputs are connected to the inputs of the first and second indicators, the pulse shaper, is entered the second pulse shaper, the fourth and fifth indicators, and the inputs of the first logical element AND-IE are connected to the outputs of both pulse shapers, and the output to the input of the Third indicator and to one of the inputs of the second and third logical elements AND-NOT, the other inputs of which are connected to the outputs of the corresponding pulse formers, the inputs of the im-; pulses are connected to the outputs of the corresponding threshold elements, and the inputs of the fourth and fifth indicators are connected to the outputs of the second and third NAND logic elements. The drawing shows the functional diagram of the proposed device for controlling the operation of digital cells. The structure of the device includes threshold elements (comparators of logical O and logical 1-) 1 and 2, shapers 3 and pulses (one vibrator), logic elements II 5-7, indicators 8-12. Additionally, this device includes block 1. the comparison, the pulse shaper Ik and the indicator 15. provide a comparison of the working (verified) signal with the reference one. Positions 16 and 17 are designated on the scheme entrance shu, py. The device operates as follows. If the input signal level is still below a certain logical O level, it turns on with indicator 8. If the input signal level constantly exceeds a certain logical 1 level, then. the indicator 12 is turned on. When the input signal passes through the levels of logic 0 and logic 1, threshold elements 1 and 2 are triggered, impulses are formed at the output of the shaper 3 and i through the AND-NE logic 6, the indicator 10 turns on for a while. Similarly, this indicator is put into action at. transition of the input signal in the opposite direction, i.e. through the levels of logical 1 and logical O. If the input pulses repeat periodically, the indicator 10 is in the on position all the time. If the minimum level of the input pulse signal exceeds the logic level O, then the pulse driver 3 does not function. Because of this, only the indicator 11 is in the on state. If the maximum level of the input signal does not reach the logical level 1, then the driver of the pulses is taken out of action. In this case, only the indicator 9 works. If you connect the probe 16 to the monitored cell and the auxiliary probe 17 is inserted into a similar operable cell, then if the input signals at the output of the comparator block 13 do not match, a mismatch signal is generated through the driver T; V5 indicator is on. This compares the verified signal with the reference signal. Practical use of the proposed device allows us to significantly speed up the process of checking and adjusting digital cells. An apparatus for monitoring digital cells, containing three indicators, two threshold 3 | Lements, the inputs of which are connected to the input of the device, and the outputs are connected to the inputs of the first and second indicators, pulse shaper, characterized in that an account of providing the ability to control digital signals with an underestimated level of the logic or with an overestimated level of logic; three I-NOT logical elements are introduced into it, the second pulse driver, the fourth and fifth indicators moreover, the inputs of the first logical element AND-NOT are connected to the outputs of both pulse shapers, and the output is connected to the input of the third indicator and to one of the inputs of the second and third logical elements AND-NOT whose other inputs are connected to the outputs of the corresponding pulse shapers, the inputs of the pulse shaper are connected to outputs, the corresponding threshold elements, and the inputs of the fourth and fifth indicators are connected to the outputs of the second and third logical elements AND-NOT. Sources of information taken into account in the examination 1, USSR Author's Certificate N 636550, cl. G 01 R 19/16, 1977. 2..Avtorskoe certificate of the USSR N-, cl. G 01 R 31/28, 1977.