SU964669A2 - Device for reading out information from punched carrier - Google Patents

Description

The invention relates to computing and information technology and can be used to enter information into a computer from perforating media.

According to the main auth. 926690 a device is known for reading information from the transceiver, which contains informational photodetectors connected to amplifiers, the outputs of which are connected to the first inputs of the And elements, subsequently connected photonically connected to the photodetector, differentiator amplifier, comparator and driver, the output of which is connected. Diien with the second inputs of the elements And, the outputs of the elements And are the outputs of the device Cl}

The disadvantage of the known device is its low reliability of reading in the start-stop mode, when the output of the synchronizing phototop | It is possible that parasitic oscillations may occur due to transient processes in the opto-electric and mechanical parts of the device. In this case, the output of the differentiating amplifier may result in an extra-t. sync pulse, which can lead to incorrect reading of information.

The aim of the invention is to improve the scope of application of the device due to the possibility of reading information from perforating media in start-stop mode.

The goal is achieved by the fact that an additional comparator is introduced into the device, the input of which is connected to the output of the photoreceiver clock signals

10 and the output - with the third outputs of the elements I.:

Figure 1 shows the functional s.hema device; 2, time diagrams, according to the principle of operation of the device.

The device contains a light source (not shown), information fotop) Receivers I, photo sensor 2 sync signals, information amplifiers 3,

20 elements And 4, differentiating amplifier. 5, main to parator 6, driver 7, additional comparator 8, information outputs 9 of the device.

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In figure 2, the signal timing diagram 10 at the output of the photo receiver of the synchronization signals in the start-stop mode, the signal form 11 at the output of the differentiating amplifier, the signal 12 at the output of the main comparator, the signal 13 at the output of the imager, the signal 14 at the input of the information amplifiers, the signal 15 at the output of the information amplifiers, a signal 16 at the output of the additional comparator, the resultant signal 17 of coincidence in time of the signals at the outputs of blocks 7 and 8.

Light from the light source, the passage through the punched tape holes is perceived by informational and synchronizing photoreceivers 1 and 2. The output signals from the informational photoreceiver outputs are fed through amplifier 3 to the first inputs of the And 4 elements, to the other inputs of the And 4 elements, the signals from the two channels of sync signal generation, of which consists of a serially connected differentiating amplifier 5, a xp of a lparatora 6 and a former 7, and the second of a comparator 8. The outputs of the AND 4 elements are informational outputs s device.

. The device works as follows.

When passing to the reading position of the synchronizing holes of the perforant (per tape) past the photodetector of the clock signals 2, the output signal forms a signal that is close to sinusoidal with a constant component (Fig. 2a).

Fig. 2a also shows a parasitic oscillation, the occurrence of which is possible only at the moment when the punched tape starts to move in the start-stop mode of reading information. This parasitic oscillation has a smaller amplitude compared to the oscillations of the main signal and can occur as a result of the transition process in the optoelectric and mechanical parts of the device and the photo-reading mechanism, when the punched tape, which is only under tension of the tension of the arm of the cassettes, can perform reciprocating movement relative to the synchronization of the photodetector and the light source.

In the continuous information reading mode, there are no parasitic oscillations.

Differential amplifier 5 converts a sinusoidal waveform with a constant component taken from the photodetector of sync signals 2 into a cosine-shaped output signal without a constant component. Figs. 2, 11 show the transformed voltage at the output of the differentiating amplifier with a parasitic oscillation at its input.

Comparator 6 converts the cosinusoidal signal taken from the output of the differentiator of amplifier 5 to a square wave signal at the & kt of changing its input signal sign (Figures 2, 12). The moment of change of the signal at the output of the comparator 6 from a positive sign. A negative one corresponds to the zero level of the differentiated signal and the maximum value of the signal taken from the photodetector 2.

In addition, the signal from the photodetector of sync signals 2 is fed to the first input of an additional comparator 8, which generates square-shaped signals at its output, which are second synchronization pulses only at those moments when the signal at its output exceeds the threshold. Figures 2, 16 show rectangular-shaped signals at the output of an additional comparator 8.

At the moment of the trailing edge of the rectangular signal of the positive sign of the comparator 6 at the output of the driver. 7 sync pulses form short duration first synchronization pulses.

Figure 2, 13 shows the parasitic excess synchronization pulse at time t.

The first and synchronization pulses gate amplified and limited by information amplifiers 3 signals on And 4 elements along the third inputs, respectively, and information pulses at the output of And 4 elements pass only with simultaneous passage of pulses from the generator 7 and from the comparator 8

The technical and economic effect of the proposed invention lies in the possibility of using the device for reading information both in continuous mode and in start-stop mode.

Claims (1)

1. USSR author's certificate 926690, cl. G 06 K 7/14, 1980.