SU1566358A2 - Device for interfacing computer and tape recorder - Google Patents

Abstract

The invention relates to computing. The interface device contains output and input channels. The output channel includes a serial asynchronous transmitter, elements EXCLUSIVE OR, a converter of rectangular pulses into a sinusoid, a frequency divider. The input channel includes a comparator, two resistors, a delay element, three one-shot, a serial asynchronous receiver, a trigger, and elements I. The invention improves the reliability of the device by reducing the sensitivity of the input channel to uneven movement of the magnetic tape. 1 il.

Description

The invention relates to computing and is an improvement of the device according to the author. No. 1474660.

The aim of the invention is to increase the reliability of operation by reducing the sensitivity of the input channel to uneven movement of the magnetic tape.

The drawing shows a block diagram of the proposed device.

The device contains output channels 1 and input 2. Channel 1 of the output includes a serial asynchronous transmitter 3, an output connected to the first input of an element SCUTTER OR 4 connected to a converter of 5 square-wave pulses into a sine wave, and a frequency divider 6. Input channel 2 includes a comparator 7, the first input of which is connected to the first 8 and second 9 resistors, delay element 10, the output of which is connected to the second input of the EXCLUSIVE OR 1 1 element, the output of the connected khkho- 71 of the first one-oscillator 12, serial asynchronous receiver 13, the second one-shot 14 and the trigger 15. Input 16 is the input of the device for connecting the clock output of the computer, input 17 is the information input of the output channel, input 18 is the analog input of the input channel, output 19 is the output of the output channel, output 20 is the information output y troystva. Element And 21 output connected to the third single-vibrator 22.

The device works as follows.

In the mode of outputting information from a computer, through the information input 17 of the output channel to the input of the serial asynchronous transmitter 3, data is generated, formed into separate

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blocks whose bytes with a frequency less than the reference frequency supplied to the device input 16, the division factor of the frequency divider b are output as consecutive asynchronous packages with start and stop bits from the output of the serial asynchronous transmitter 3 and arrive at the second input of the first element EXCLUSIVE OR 4, the first input of which receives a synchronizing signal from the output of the frequency divider 6. As a result, at the output of the EXCLUSIVE OR 4 element, a two-phase (Manchester) modulation signal is generated. From the output of the converter 5 square-wave pulses into a sine wave at the output 19 of the output channel, the information is fed to the input of a cassette recorder.

In the input mode, the processed information from the cassette recorder through the input 18 of the input channel enters the comparator 7, at the output of which pulses with steep fronts are formed. These pulses are fed to the inputs of the EXCLUSIVE OR 11 element directly and through the delay element 10 and converted into short pulses corresponding to each front of the original signal at the output of the comparator 7. The duration of these pulses is equal to the delay time of the delay element 10. From the output of the EXCLUSIVE or 11 element, the pulses are fed to the input of the restarting first one-shot one, the time of which specifies the circuit is set to 0.75 periods of changing one bit of consecutive asynchronous packages. At the output of the first one-shot 12, the pulses appear only when the bits of the consecutive asynchronous messages change and the trigger 15 is sent to the opposite state each time. From the single output of the trigger 15, the recovered sequence of asynchronous packages arrives at the information input of the serial asynchronous receiver 13. As a result, the output of the serial asynchronous receiver 13, which is synchronized by signals from the output of the third one-shot 22, receives data read from a cassette recorder through the output 20 of the input channel.

Setting the initial state of the trigger 15 occurs first

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The output bit of the second one-shot 14 is set to 12 or more periods of changing one bit of consecutive asynchronous parcels. The maximum number of periods during which the bit value does not change, 11 (for all units in the data byte, a unit in the check bit and 2 stop bits). Thus, the second one-shot 14 restarts during the entire data block, holding at its output the trigger enable signal 15 from the signals from the output of the first one-wave 12. During the inter-pause, when the output of the asynchronous transmitter 3 is one, and In the absence of changes in the information, the first one-shot 12 does not restart the second one-shot 14; the last, after the adjustment time of its C-circuit has elapsed, sets up a trigger 15 on a single input, which ensures its correct polarity before ihodom start bit of the next block serial asynchronous parcels.

The third one-shot. 1 is triggered by pulses from the output of the EXCLUSIVE OR 11 element, arriving at its input through element 21, the second input of which receives a signal from the output of the third single-oscillator 22, prohibiting its restart for a time equal to 0.75 periods of changing one bit of consecutive asynchronous packages. Thus, from the output of the third one-shot 22 to the synchronization input of the serial asynchronous receiver 13, a clock synchronization is received, phased with the 15 bits of the received data recovered at the output of the trigger.

Claims (1)

Invention Formula A device for interfacing a computer with a tape recorder according to ed. St. No. 1474660, characterized in that, in order to increase the reliability of operation by reducing the sensitivity of the input channel to the uneven movement of the magnetic tape, an And element is inserted into the input channel, and a third single vibrator, the input of which is connected to the output of an And element, and the output the second input of the serial asyn51566358 the chronical receiver and the first input is assigned to the output of the element ISYUSHCHYUPKE of the element AND, the second input of which is connected via the OR input channel.