SU1094052A1 - Process for multichannel magnetic recording - Google Patents

Abstract

MULTI-CHANNEL MAGNET RECORDING METHOD by temporarily separating the channels of the converted input analog signals into pulse-modulated signals, characterized in that, in order to increase the information recording density, the analog signal of each channel is converted into amplitude-pulse-modulated signals, they are temporarily compressed by 2.5 -K-gp times (where K is the number of discretes for one smallest period T of an analog signal when converted into amplitude-pulse-modulated signals, gp is the number of channels), forms A sequence of amplitude-pulse-modulated signals from at least K samples with intervals between samples not less is transmitted in each channel and the samples of amplitude-pulse-modulated signals are converted into period-pulse signals, and the time division of the channels is recorded with sync pulses in the intervals between samples.

Description

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SUBSTANCE: invention relates to instrument making, namely to methods of multichannel recording on magnetic media. The known method of multichannel magnetic recording by temporarily separating the channels of frequency-modulated signals 1. The disadvantages of the method are the asynchrony of samples of each channel, depending on the information content of other channels, which involves the use of a complex structure during playback, as well as the difficulty of recognizing the channel number. In addition, the use of the density characteristic of a magnetic recording in the implementation of the method is incomplete. The periods of the signals belonging to the adjacent measuring channels may have extreme values of duration corresponding to the minimum and maximum levels of the measuring signals, which is not the case when registering one frequency-modulated signal in one magnetic recording channel. In order to eliminate the transient interchannel effect arising in this case and to maintain a satisfactory recording accuracy of the multichannel signal in the magnetic recording channel, calculated to record one frequency-pulse-modulated signal, the recording density falls on y1 "to reduce and switch to the next more low frequency ranges from the standard range. This ultimately leads to a decrease in the information recording density. The closest in technical essence to the invention is a method of multichannel magnetic recording by temporarily separating the channels of the converted input analog signals into pulse-modulated signals. From the modulated pulse sequences of the first and second channels, an auxiliary pulse sequence is formed in which the leading edge of the modulated pulse sequence of the first channel is converted into the falling edge of the pulse duration of this modulated signal. Subtracting the signal of the modulated pulse sequence of the second channel from the signal of the auxiliary pulse sequence, get a compressed signal. This signal refers to a multi-level and multi-valued rectangular signal due to the fact that there are more than two levels in each cycle of the signal. The positive edges of the compressed signal correspond to the starting point of the sawtooth voltage, which ensures the necessary synchronization during the playback of the result of the recording. The time position of the negative edges of the compressed signal varies in accordance with the fluctuations of the input signals of the first and second channels and is used in demodulation during the playback of the result of the recording. Areas with a repeating period T serve as clock signals. They coincide with the positive fronts that have the amplitude value of the compressed signal. The remaining opposite-polar edges, whose temporal position varies in accordance with the oscillations of the channel input signals, are two times smaller than the amplitude value of the compressed signal. This ensures that during the reproduction of the result of the recording, recognition of the synchronizing signal and the modulated signals 2. However, the known method does not allow the registration of a large amount of continuous information contained in the signals of the input channels. The aim of the invention is to increase the information recording density. The goal is achieved by the method of multichannel magnetic recording by temporal separation of the channels of the converted analog input signals into pulse-modulated signals. The analog signal of each channel is converted into amplitude-pulse-modulated signals and temporarily compressed. t times (where K is the number of discretes for one smallest period T of an analog signal when converted into an amplitude-pulse-multiplied signal; w is the number of channels), each channel is formed The accuracy of the samples of amplitude-pulse-modulated signals from it is less than K discretes with intervals between samples not less and transforms the samples of amplitude-pulse-modulated signals into samples of pulse-period signals, and the time division of the channels is carried out with the recording of clock pulses in the intervals between samples. Operations with signals of different channels allow one to obtain a uniform compaction of these signals without loss of counts, to apply the method of periodic-pulse modulation, and not to use the multi-level form of the recording current to register the compressed signals to a magnetic carrier. The method is carried out as follows. The analog input signal of each channel is divided in time into separate uniform sections, which can be called a sample of the input signal. Each sample may consist of many periods of the measurement signal, for example, two periods of the highest frequency of the measurement signal. The original signal sample is converted to a new one, containing the previous number of periods of the measuring signal, but taking a shorter time. The process of time compression occurs with the help of several operations, including the conversion of the measuring signal into amplitude modulated pulse discretes, memorization and subsequent reading them at an accelerated rate. The number of samples per one smallest period T of the analog signal is chosen based on the required accuracy of the signal recovery during reproduction and demodulation.

Thus, temporal compression is performed 2.5-Kt times, where K is the number of samples per one smallest period T of the analog signal; m is the number of channels.

Signals from a group of channels intended to register on one track of a magnetic carrier are temporarily compressed according to the proposed method so that the signal portions corresponding to different channels are separated by time intervals. The duration of the time interval is chosen based on the possibility of registering synchronization pulses in it. Optimal results are obtained when the duration of the time interval is not less than the duration of -T.

The amplitude-modulated pulse signal is then converted into a period-pulse-modulated sequence. The latter, before registering on a magnetic carrier, receives an additional transformation, which consists in recording in the intervals between samples of clock pulses.

The sequence of actions with input signals and pulsed sequences represents (| isic process of transferring the frequency spectrum of the original signals to the upper part of the linear spectrum, carried out alternately in time for all channels, which are assigned a certain place in the general flow of elements representing the multichannel signal. gaps existing between samples and containing sync pulses are used when reproducing the result of recording a multichannel signal for synchronization a channel and the organization of the reverse transfer of the frequency spectrum during the restoration of the original signals.

FIG. 1 shows the time diagrams of the proposed method of multi-channel recording, signals on a magnetic carrier; in fig. 2 is a block diagram of one possible embodiment of an apparatus for carrying out the proposed method.

The device contains the source 1 of the signal of the first channel, the source 2 of the signal of the second channel, the circuit 3 of sampling and storing the amplitude-pulse-modulated signal of the first channel, the circuit 4 of sampling and storage of the amplitude-pulse modulated signal of the second channel, the summation circuit 5, connected in series to the modulator 6, circuit AND 7, circuit OR 8, trigger 9, recording amplifier 0, recording head 11. Elements I-11 comprise an information signal recording unit 12. FIG. 2 shows one such block, but their number may be greater. The device also contains a generator 13, a trigger .14, first, second, third, fourth and fifth dividers 15-19, first, second and third drivers 20-22 pulses, first and second switches 23 and 24, generator 25 sawtooth voltage. Elements 13-25 constitute the synchronization unit 26. The serially connected circuit OR 27, trigger 28, recording amplifier 29 and recording head 30 together constitute a clock signal recording unit 31.

The synchronization unit 26 has, the first output 32, coinciding with the output of the first driver 20 pulses, the second output 33, which coincides with the output of the second driver 21 pulses, the third output

34, coinciding with the output of the third shaper 22 pulses, the fourth output

35 coinciding with the output group of the second switch 24, fifth output 36 coinciding with the output of the sawtooth generator 25, the sixth output 37 coinciding with the output group of the first switch 23. The clock recording unit 31 has the first input 38 coinciding with the first input of the circuit OR 27, the second input 39, which coincides with the second input of the circuit OR 27. Block

12 recording information signal has an input 40, which coincides with the combined first groups of inputs of circuits 3 and 4 of the sample and storage of the amplitude-pulse-modulated signal, the second input 41, which coincides with the first input of the modulator 6, the third input 42, which coincides with the combined second groups of inputs of the circuits 3 and 4 of the sampling and storage of the amplitude-modulated signal and the group of inputs of the circuit And 7, the fourth input 43, which coincides with the second input of the circuit OR 8. In block 12 of the information signal recording, the output of the source 1 of the signal of the first channel under is connected to the input of circuit 3, the output of source 2 is connected to the input of circuit 4, the output of circuit 3 is to the first input of circuit 5, the output of circuit 5 is connected to the second input of the amplitude-modulated signal, the output of circuit 5 is connected to the second input of the modulator 6. In block 26, the synchronization output of the generator

13 is connected to the trigger input 14, the first output of which is connected to the first input of the first divider 15, and the second output is connected to the first inputs of the dividers 16-19, the output of the first divider 15 is connected to the input of the first shaper 20 pulses, the output of the second divider 16 - to the input of the first divider 15, and the second output is connected to the first inputs of dividers 16-19, the output of the first divider 15 is connected to the input of the first shaper 20 pulses, the output of the second divider 16 - to the input of the second shaper 21 pulses, the output of the third divider 17 - to the third shaper The pulse generator 22, the output of the second splitter 19 is connected to the first input of the first switch of the fourth splitter 18 - to the input of the sawtooth generator 25 and to the first input of the second switch 24. The output of the first, the driver 20 of the pulses is connected to the second inputs of dividers 1-5-19 and switches 23 and 24. The first output 32 of block 26 is connected to the first input 38 of block 31, the second output 33 of block 26 to the second input 39 of block 31, the third output 34 of block 26 to the fourth input 43 of block 12, the fourth output 35 of block 26 - with the third input 42 of the block 12, the fifth output 36 of the block 26 - with w ring 41 input unit 12, an outlet 37 of the sixth unit 26 - to the first input unit 12. The apparatus operates as follows. In block 26 synchronization generator 13 generates a sequence of pulses. which on the trigger 14 is converted into the first and second pulse sequences. The first pulse sequence by divider 15 and shaper 20 pulses is converted into a marker sequence, divider 19 and the first switch 23 is converted into polling pulses of input signals. A first pulse sequence by a divider 18, and the second switch 24 is converted into read pulses of samples of input signals. The first pulse sequence by the divider 18 and the sawtooth generator 25 is converted into a sawtooth signal, the divider 17 and the driver 22 are converted into a sequence of clock pulses. The second pulse sequence by divider 16 and shaper 21 is converted to a third pulse sequence. The synchronization unit 26 generates a marker sequence at the first output 32, a third pulse sequence at the second output 33, a sequence of sync pulses at the third output 34, readout samples of the measurement signals at the fourth output 35, and input polling pulses at the fifth output 36. In the clock recording unit 31, the marker sequence and the third pulse sequence are converted by the OR circuit 27 to a service pulse sequence, which is converted by the trigger 28 into a recording output signal. The recording amplifier 29 and the recording head 30 register the output overhead signal on a single magnetic track. The reproduced clock recording result is used to distinguish and recognize signals and convert the frequency spectrum of the reproduced recording result of information signals to the original frequency spectrum that these signals have at the output of sources 1 and 2 signals. In the information signal recording unit 12, the signal of the first channel (Fig. 1a) from source 1 and the signal of the second channel (Fig. 1 b) from source 2 are sampled in time by polling pulses of the input channels in circuits 3 and 4 of sampling and storage of pulse-amplitude the modulated signal and are converted respectively to the first amplitude-pulse-modulated sequence of the first channel (Fig. 1c) and the first amplitude-modulated sequence of the second channel (Fig. 1g), which are memorized; Reading pulse amplitude-mo-. The duplicated sequences occur at the second clock of the marker sequence by read pulses arriving at circuits 3 and 4 from input 42, and at the outputs of circuits 3 and 4, respectively, the second pulse-amplitude-stimulated sequence of the first channel (Fig. 1 d) to the second pulse-amplitude are formed. -modulated sequence of the second channel (Fig. 1 e). The summation circuit 5 adds the second amplitude-pulse-modulated sequences, the result of the addition on modulator 6 is converted by the signal from input 41 to the first pulse-period-modulated sequence (Fig. I g), which is gated to the diagram from And with the signal from input 41. is converted into a second period-pulse modulated sequence (Fig. 1 h) in which there are pauses. In the OR 8 scheme, the pauses are filled with synchronization pulses coming from input 43, and a third period-pulse-modulated sequence is formed (Fig. 1i). A trigger 9 converts a third period-pulse-modulated sequence into an output information signal (FIG. IK), in which the modulated pulse sequences are separated by sync pulses. The reproduced sync pulse sequence record is used to distinguish input channel signals and phasing the modulated pulse sequence when the frequency spectrum returns (time stretched) of the reproduced continuous signal to the original frequency spectrum that these signals had at sources 1 and 2 output. Trigger 9 , recording amplifier 10 and recording head 11, the output information signal is recorded on the same track of magnetic media.

In the remaining blocks of 12 recording information signal. Registration on the track

The magnetic carrier of the measuring channel signals is similar.

With the proposed method, in comparison with the known, the amount of recorded information increases to the extent that the information content of the period-pulse modulation exceeds the information content of the pulse-width modulation, and the two-level recording method without returning to zero exceeds the recording density level with zero. .

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Claims (1)

METHOD OF MULTI-CHANNEL MAGNETIC RECORDING by temporarily separating the channels of the converted input analog signals into pulse-modulated signals, characterized in that, in order to increase the recording information density, the analog signal of each channel is converted into amplitude-pulse-modulated signals, they are temporarily compressed into 2, 5-K-t times (where K is the number of samples for one smallest period T of the analog signal when converted to amplitude-pulse-modulated signals, m is the number of channels), form each channel, a sequence of samples of amplitude-pulse-modulated signals from at least K samples with intervals between samples of at least - ^ - T and transform samples of amplitude-pulse-modulated signals into samples of periodically-pulse signals, and the time division of channels is carried out with recording of clock pulses in intervals between samples. g