SU1324063A1 - Device for monitoring reproducing unit - Google Patents

Abstract

The invention relates to instrumentation. The purpose of the invention is to improve the accuracy of control. The control line 5 of the delay, changing the control signal on the bus 18, can change the signal delay time, which allows simulating the skew of the reproducing head and determining the operation stability of the reproducing unit 17 depending on the skew of the reproducing head. From the playback unit 17, the signal is fed to the input of the oscilloscope channel 14. To determine the noise immunity by the amplitude of the monitored playback unit 17 using attenuator 4, the amplitude of the test signal is reduced by monitoring the oscillogram of the output signal of the playback unit 17 on the oscilloscope screen. To determine the noise immunity by density, the frequency of oscillator 1 generation is increased, and to determine the stability by skew of the reproducing head, the time delay of the sync signals relative to the information signal is changed. 2 Il. Too with ot with Fig. /

Description

The invention relates to instrument engineering and can be used to control the blocks of the recording of digital magnetic recording apparatus.

The aim of the invention is to improve the accuracy of the control.

FIG. 1 shows a functional diagram of the device; in fig. 2 - timing diagrams explaining the principle of operation of the proposed device.

The device contains a signal generator 1, connected by its output to the first inputs of comparators 2 and 3, to the input of attenuator 4 and to the input of the controlled delay line 5, the outputs of sources 6 and 7 of the reference voltage are connected to the second inputs of the comparators 2 and 3, respectively , the outputs of Comparators 2 and 3, respectively, are connected to the first and second inputs of the AND 8 element, connected by an output through a test driver 9 to a control input of an analog switch 10, connected by an information input to an output of an attenuator 4, and the output through a filter 11 are low x frequencies with the input of video amplifier 12, with the input of inverting video amplifier 13 and with the first input of the recorder - oscilloscope 14, the output of controllable delay line 5 is connected to the inputs of video amplifier 15 and inverting video amplifier 16, the outputs of video amplifier 12 and inverting video amplifier 13 are connected to information inputs of block 17 playback, and the outputs of the video amplifier 15 and the inverting video amplifier 16 are connected to the synchronization inputs of the playback unit 17, the output of which is connected to the second input of the oscilloscope 14, controlling The input of the controllable delay line 5 is connected to the control thickness 18.

The device works as follows.

From the output of the generator 1, the signal (Fig. 2a) is fed to the inverting input of the comparator 2 and the non-inverting input of the comparative switch 10 is fed to a sinusoidal signal adjusted in amplitude using an attenuator 4. As a result, at the output of the analog key 10, a code sequence of sinusoidal pulses truncated along the fronts (Fig. 2d) is formed, which, when passing through the low-pass filter 11, is converted into a code sequence of bell-shaped pulses (Fig. 2e), i.e. in a form close to the shape of real signals reproduced from a tape by a magnetic head of a digital magnetic recording apparatus, and due to the truncation of the fronts of sinusoidal pulses, it is possible to achieve a high pin density: from the lobular pulses (for example, the first and second pulses in Fig. 2e). The code sequence of the bell-shaped pulses is displayed on the screen of the oscilloscope 14, and is also fed to the video amplifier 12 and the inverting video amplifier 13.

20 The received paraphase signal simulating the reproduced signal is fed to the information inputs of the monitored playback unit 17, and the sync inputs of the playback unit 17 are supplied with a paraphase signal from the video amplifier 15 and the inverting video image 16 generated from a sinusoidal signal fed through the controlled delay line 5 from the output generator 1. In this case, by controlling the delay line 5, by changing the control signal on the control bus 18, the delay time of the synchronization signal relative to but an information signal, which makes it possible to simulate the skew of the reproducing head and makes it possible to determine the stability of the operation of the reproduction block 17 depending on the skew of the reproducing head.

From the output of the playback unit 17, the signal is fed to the input of the second channel

25

thirty

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torus 3, and the second inputs of the comparator-40 dual-channel oscilloscope 14. If the counters 2 and 3 are fed the same abnormal playback unit 17 to the positive value of the positive and negative-vein and tuned, on the screen of the oscilloscope

the exact level of voltage (dotted line control the stable waveform

45

FIG. 2a) from sources 6 and 7 of the reference voltage. From the outputs of comparators 2 and 3, the comparison signals are fed to the input of the element 8, which forms a sequence of pulses (Fig. 26), with the middle of each pulse corresponding to passing through the zero level of the sinusoidal signal (Fig. 2a). The formed JQ sequence of rectangular pulses (Fig. 26) is fed to the test driver 9, which forms the code sequence (Fig. 2c). Formed code sequence arrives

(Fig. 2e), with the leading and falling edges of the pulses corresponding to the maximum and minimum of the bell-shaped pulses, respectively. To determine the noise immunity on the amplitude of the monitored playback unit 17, it is sufficient to attenuate the amplitude of the test signal using attenuator 4 by monitoring the oscillogram of the output signal of playback unit 17 on the screen of the oscilloscope 14. To determine the noise immunity in terms of the recording density, it is sufficient to increase the oscillator 1 generation frequency, and to determine the stability by the skew of the reproducing head, it is enough to change the delay time of the sync signals relative to the information signal.

on the controlling input of the analog switch 10, ensuring that it opens only for the duration of the action of the pulses of the code sequence, and on the input of the analog switch

ten

The key 10 receives a sinusoidal signal adjusted in amplitude by means of an attenuator 4. As a result, at the output of the analog key 10, a code sequence of sinusoidal pulses truncated along the fronts (Fig. 2d) is formed, which, when passing through the low-pass filter 11, is converted into a code sequence of bell-shaped pulses (Fig. 2e), i.e. In a form close to the shape of real signals reproduced from a tape by a magnetic head of a digital magnetic recording apparatus, and due to the truncation of the fronts of sinusoidal pulses, it is possible to achieve a large pin density from longitudinal pulses (for example, the first and second pulses in Fig. 2e). The code sequence of the bell-shaped pulses is displayed on the screen of the oscilloscope 14, and is also fed to the video amplifier 12 and the inverting video amplifier 13.

0 The received paraphase signal, imitating the reproduced signal, is fed to the information inputs of the monitored playback unit 17, and the sync inputs of the playback unit 17 are supplied with a paraphase signal from the video amplifier 15 and the inverting video image 16 generated from a sinusoidal signal fed through the controlled delay line 5 from the output generator 1. In this case, by controlling the delay line 5, by changing the control signal on the control bus 18, the delay time of the synchronization signal relative to of the information signal, that allows to simulate skewed reproducing head and allows to determine stability of the reproducing unit 17 according to Skew reproducing head.

From the output of the playback unit 17, the signal is fed to the input of the second channel

five

0

five

0 two-channel oscilloscope 14. If you control a stable oscillogram

five

Q

five

(Fig. 2e), with the leading and falling edges of the pulses corresponding to the maximum and minimum of the bell-shaped pulses, respectively. To determine the noise immunity on the amplitude of the monitored playback unit 17, it is sufficient to attenuate the amplitude of the test signal using attenuator 4 by monitoring the oscillogram of the output signal of playback unit 17 on the screen of the oscilloscope 14. To determine the noise immunity in terms of the recording density, it is sufficient to increase the oscillator 1 generation frequency, and to determine the stability by the skew of the reproducing head, it is enough to change the delay time of the sync signals relative to the information signal.

Claims (1)

Invention Formula the inputs of the element I, connected by the output through the test signal driver with the control input of an analog switch, whose information input is connected to the attenuator output, and the output through a low-pass filter to the inputs of the first video amplifier, the first inverting video amplifier, and the first input of the recorder, the output of the controlled line delay connected to the inputs of the second video amplifier A device for controlling a reproducing unit, comprising a generator, a reproducing unit, an AND element, a delay line and a recorder, characterized in that, in order to increase the control accuracy, two reference voltage sources, two comparators, a test driver, an attenuator, an analog key, low pass filter, two video amplifiers Yu and the second inverting video amplifier, and two inverting video amplifiers, the outputs of the first video amplifier and the first the output of the signal generator of the inverting video amplifier is connected to the first inputs of the first and second signals to the information inputs of the reparator unit, to the attenuator input and to the product, the outputs of the second video amplifier to the delay line, the outputs of the first l and second inverting video amplifiers and the second sources the reference voltage of the bodies is connected to the synchronization inputs connected to the second inputs of the first and playback units, the output of which is the secondary comparators, respectively, is output to the second input of the the first and the second comparators; the connecting input of the delay line is connected cheny respectively to the first and second with the management team. but / - / XNr - y -V the inputs of the element I, connected by the output through the test signal driver with the control input of an analog switch, whose information input is connected to the attenuator output, and the output through a low-pass filter to the inputs of the first video amplifier, the first inverting video amplifier, and the first input of the recorder, the output of the controlled line delay connected to the inputs of the second video amplifier  and the second inverting video amplifier, the outputs of the first video amplifier and the first -X :: / - and I PMN