SU1183927A2 - Apparatus for measuring parameters of television receiver frame scan microcircuits - Google Patents

Abstract

DEVICE FOR MEASURING THE PARAMETERS OF THE MICROSHEM OF PERSONNEL SCAN TELEVISION RECEIVER according to the aut. St. No. 1057892, characterized in that, in order to improve speed, a synonisation indicator, an additional resistor to the optocoupler, a DC amplifier, two elements of sampling and storage, a pulse shaper, two single vibrators, and the variable resistor are designed as a resistor body resistor optocoupler. the inputs of both single-shotrs connected together are connected to the output of the clock synchronizing generator, the output of the first one-shot through the pulse shaper is connected to the control input of the first element of the sample and storage, the output of which is connected to the signal input of the second element of the sample and storage, the output of which is connected through the DC amplifier the first output of the additional resistor optocoupler, the second output of which is connected to the common alarm, the output of the second one-shot is connected to the control input the second element of the sample and storage, the signal input of the first element of the sample and storage is connected to the output of the zero-level lock, and the first and second inputs of the indication block of synchronization are connected respectively to the output of the clock generator and the input of the amplifier-limiter. Ioz

Description

The invention relates to instrumentation and can be used in measuring the parameters of linear integrated circuits for frame scanning of a television receiver. The purpose of the invention is to increase the speed by automating the installation operations and controlling the synchronization mode between the clock generator frequency and the oscillation frequency generated by the controlled chip. Fig. 1 shows the structures on the control device scheme on FIG. 2 and FIG. 3 - voltage plots at the inputs and outputs of the elements and units of the device. The device contains a clock pulse generator t, a resistor optocoupler 2, a time specifying a capacitor 3, an oscilloscope 4, a latch 5 of the zero level, the first element 6 of sampling and storage, a delay element, the first comparator 8 ,. reference source 9, integral 10, first resistor optocoupler 11, equivalent to 12 load, current sensor 13, second comparator 14, fault indicator-15 15, limiter amplifier 16, time interval meter 17, first additional element 18 sampling and storage, the first one-shot 19, a pulse shaper, the second additional element 21 bypass and storage, the second one-shot 22, a DC amplifier 23, a synchronization indicator 24. The inputs of both one-shot 19 and 22 are connected to the output of the generator 1 synchronizing pulses, the output of the first one-shot 19 is connected through the driver 2 of the pulses and the first element 18 of selection and storage to the first input of the second element 21 of the sample and storage, the second input of which is connected to the second one-shot 22. The output of the second element 21 of the sample and storage is connected through an amplifier 23 to the input of the resistor optocoupler 2, and the inputs of the synchronization indicator 24 are connected respectively to the output of the generator 1 and the input of the amplifier-limiter 16, latch input 5 is co-connected with current sensor 13, latch 5 output through series-connected sampling and storage element 6, comparator 8 and integrator 10 are connected to a LED of a resistor optocoupler 11, reference inputs of comparators 8 and 14 are connected to source output 9 of a reference voltage The signal input of the comparator 14 is connected to the output of the sampling and storage element 6. The input of the delay element 7 is connected to the output of the generator 1, and the output is connected to the control input of the sample and storage element 6 and to the gated INPUT of the comparator 14. The device operates as follows. In the presence of synchronization between the input clock pulses of the generator 1 and the output voltage of the generator of the pshtoobrazny voltage of the measured microcircuit, the tracking frequency fj.j. sync pulses of generator 1 are equal to the frequency f of the output sawtooth voltage of the microcircuit, the value of which is determined by fj, (Rp Cf), i.e. the value of the mode-setting elements 2 and 3, the resistor optocoupler and the capacitor, respectively. The presence of this condition is determined by the control two-beam oscilloscope 4 with respect to the frequency 1.. At the input of the test chip from generator 1, a sync pulse is supplied with the specified parameters (Fig. 25). The output voltage of the power amplifier of the tested chip (Fig. 2d) is fed to the input of latch 5 of the zero level, which binds the lower level of the pulse to the zero potential (Fig. 2nd). From the output of the latch 5 of the zero level, the signal enters the input of the element 6 of the sample and storage, which carries out the switching of this signal at the moment of time Tp (Fig. 25). In order for the sampling and storage element 6 to sample the voltage at the required time, namely, at the time corresponding to the tip of the current pulse in the load (Figure 2d), the control pulse is formed from the sync pulse by delaying the latter by a fixed the time value is equal to the average value of the time of reverse frame sweep (Fig. 2e). The signal from the output of the sample and storage element 6 is fed to the input of the comparator 8, where it is compared with the sample

By the mean voltage of the source 9 of the reference voltage (Fig. 2,), the difference error signal is fed to the integrator 10, from the output of which goes to the resistor optical fiber. the optocoupler 11 and changes its resistance to a predetermined value corresponding to the steady state pulse of the output current equal to the predetermined value (IA). In the case when the circuit under test does not provide an output current of a given value through the equivalent of 12 load, the rejection is performed by an additional device containing a comparator 14 and a reject indicator 15. The rejection is performed at the moment of arrival of the control pulse from the output of the delay element 7 to the gated input of the comparator (Fig. 2B). When measuring the duration of the return stroke, a limiting amplifier 16 is provided in the device, which indicates the peak of the output voltage pulse (phng 2 b) of a vertical scanning chip before the measurement process. The actual measurement of Cox (Fig. 25) is carried out after setting a predetermined value of the amplitude of the sawtooth current with a time interval meter 17.

When going from measuring the parameters of one microcircuit to measuring the parameters of another, the synchronization condition between the input clock pulses of the generator 1 and the output voltage of the sawtooth generator of the measured chip (i.e., p) i.e. fcn / fp 1 In the absence of a synchronization condition, the device operates as follows. .

The signal input of the first additional element 18 for sampling and storage receives a sawtooth voltage removed from the output of latch 5 of the zero level (Fig. 3H), and to its control input - control pulses (Fig. 3m), which determine the duration of the sampling of sawtooth (i IMC) and sample storage time (S 10 ms). These pulses are formed by a single vibrator 19, which in turn is triggered by the sync pulses of the generator 1. One, the vibrator 19 generates pulses of duration t equal to the storage time of the first additional element

18 sampling and storage. The output pulses of the one-shot (Fig. 3.K) trigger the pulse shaper 20, the output pulse duration of which is equal to the sawtooth voltage sampling time (si ms) of the measured chip (Fig. 3 /) of the first additional sampling and storage element 18.

The duration of the control pulse of the first additional sample and storage element 18 is chosen to be rather small (), but short times require a small capacitance value of the storage capacitor. On the other hand, long-term storage (l / 10 ms) of the signal requires a greater storage capacity. Dp of obtaining long-term storage of the selected signal value with high accuracy

: a second extra-sampling and storage element 21 is introduced, which, unlike the first, has a large storage capacity (10 ms). .

The control pulses are generated by the one-shot 22 and are synchronized with the pulse frequency following the one-shot input from the clock generator output (Fig. 3L). The output signal of the second additional element 21 for sampling and storage is amplified by the DC amplifier 23 and fed to the LED of the resistor optocoupler 2, the size of its photoresistor, which is the mode-producing elec- tron, is determined. the copied microcircuit.

In the steady state (if synchronization conditions are different), the sampling pulse of the first additional element 18 of the sampling and storage occurs in the vicinity of the center of the sawtooth voltage produced

(generator of the measured microcircuit

Ffig Zn), i.e. samples the nominal voltage value.

If the frequency of the saw voltage is increased (Fig. 3 o), the sampling pulse is shifted to the left, so the first additional sample and storage element 18 samples the higher voltage (Fig. 3). An increase in the error voltage increases the current through the LED of the optocoupler 2 and reduces the size of its photoresistor, which leads to a decrease in the frequency of the sawtooth voltage of the chip to a value corresponding to the synchronization frequency.

Similarly, a decrease in the frequency of the sawtooth voltage of the microcircuit, for any reason, relative to the nominal value, causes a change in the phase of the pulse of the first additional element 18 of the sample and storage, shifting it to the right (FIG. 3). Voltage sampling is done

later, which leads to a decrease in the error in the mode-setting circuit and thereby to an increase in the frequency of the saw-tooth voltage until the moment of synchronization.

In the absence of synchronization (chip failure), the chip is broken up by the synchronization device 24, which can be polled in software.

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Claims (1)

DEVICE FOR MEASURING PARAMETERS OF MICROSCRIPT OF PERSONNEL SCAN OF TELEVISION RECEIVER by ed. St. No. 1057892, characterized in that, in order to improve performance, it includes an indicator of the presence of synchronization, an additional resistor optocoupler, a DC amplifier, two sampling and storage elements, a pulse shaper, two one-shot, and the variable resistor is made in the form of an additional resistor optocoupler connected together the inputs of both single vibrators are connected to the output of the synchronizing pulse generator, the output of the first single vibrator through a pulse former is connected to the control input the first sampling and storage element, the output of which is connected to the signal input of the second sampling and storage element, the output of which through a DC amplifier is connected to the first output of an additional resistor optocoupler, the second output of which is connected to a common bus, the output of the second one-shot is connected to the control input of the second sampling element and storage, the signal input of the first sampling and storage element is connected to the output of the zero level latch, and the first and second inputs of the indication unit for the presence of synchronization are connected us respectively yield clock generator and the input of the limiter-amplifier. SU, „, 1183927 1 . 1183927