JPS595409A - Recording and reproducing system of sound recording magnetic tape - Google Patents

Abstract

PURPOSE:To obtain a good binary signal which is not influenced by distortion of a waveform, by modulating a binary signal to a square wave which becomes point-symmetrical to a base line at every its variation point, recording it in a magnetic tape and reproducing it. CONSTITUTION:Monostable multivibrators 4, 5 detect rise and fall from a serial binary signal 2, and output detecting signals 6, 7 from the respective output terminals -Q. The signal 6, 7 are inputted to a logical gate 8, and a gate output signal 9 being in the shape of taking OR of a square wave is generated. The signal 9 is supplied to a monostable multivibrator 22, and a square wave whose signal width which makes its fall time point a start point is equal to the signal 9 is generated. A negative square wave signal 23 outputted from an output terminal -Q of the monostable multivibrator 22 is inverted by an invertor 24 and becomes a positive square wave signal 25. On the other hand, the gate output signal 9 becomes a negative square wave signal 27 by an invertor 26. These signals 25, 27 are synthesized and becomes a recording signal 28.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a system for recording binary signals on a recording magnetic tape and a system for reproducing recorded data.

Generally used recording magnetic tapes are inexpensive, and recording and reproducing devices (tape recorders) using these tapes are small and inexpensive.

Therefore, a method has been put into practical use in which predetermined binary signals or digital data are recorded and reproduced on a recording magnetic tape without using an information recording tape and a recording/reproducing device for this purpose. Typical of these are the Canris City Standard system and the Nappo [-1 City Standard system.

FIG. 1 shows the modulation waveform of a binary signal (Oll) according to the CanLiscity standard system. In this method, the signal it_oit is modulated by 4 waves of 1200 tlz, and the signal "1" is modulated by 8 waves of 2400 Hz. Therefore, signal redundancy is high and data transfer speed is extremely slow.

Figure 2 shows Sappo [f based on the city standard method]
This represents the modulation waveform of the binary signal (0, 1) of il-. This method is an improved version of the Kansas City Standard method, in which the edge spacing of the signal is set wide for the signal "0'" and narrow for the signal "1". Figure 3 shows this system.
．． 1) represents a modulated waveform. This system can achieve a transfer rate of 3,200 baud using magnetic recording tape, which is approximately 11 times faster than the Kansas City Standard system.

However, in this Zappo 1 City Standard 6 type, the modulation waveform is asymmetrical at the conversion point between "O" and "1" of the signal. Therefore, when playing data from tape,
The baseline fluctuates greatly and the reproduced waveform becomes blocked. This makes it difficult to adjust the demodulation circuit. In other words, the threshold value V for detecting the signal “1°” from the reproduced waveform
In a signal portion where T□ is relatively high, the width of the signal "1" is detected to be narrow, and there is a risk that the signal may be mistakenly detected as "0".

In order to improve the above points, a recording angle generation system for recording magnetic tape using two channels has been proposed. FIG. 4 is for explaining this system, and a in the figure shows a serial input r binary signal as an example. In this method, only the signal r(11+) is modulated in one channel (b in the same figure) to generate a point-symmetrical rectangular wave. At the point where the signal "1" is continuous, the rectangular wave is continuously generated according to the number of consecutive "1" signals. In the other channel (C in the same figure), the signal “0°
′ is modulated to similarly generate a point-symmetric rectangular wave with the same width. Similarly, the rectangular waves are made continuous at consecutive points.

In this method, two channels of recorded data are simultaneously generated, and a clock signal is created by calculating the logical sum of the reproduced waveforms corresponding to FIG. This clock signal is then used to reproduce binary signals from each channel. Naturally, therefore, a stereo type cheap recorder capable of recording and reproducing two channels simultaneously is required. In other words, the tape recorder had the disadvantage of becoming larger and more expensive.

In view of these points, the present invention provides a monaural cheap play]-
The purpose of the present invention is to provide a recording/reproducing method for a recording magnetic tape which can use a magnetic tape and which can easily reproduce binary signals.

In the present invention, point-symmetric rectangular waves are generated only at points where the binary signal changes from 0'' to 1'' or vice versa, and are recorded on a recording magnetic tape.

Re(1) For the waveform, set the threshold on the side where no ringing occurs with the baseline as the M quasi.Then, change the signal level at the timing of rising or rising at this threshold. 2
Play the advance signal. In this method, since there is no DC component in the recording signal, the baseline of the reproduced signal hardly changes. Also, this regenerated signal is 2
Since it represents the changing point of the forward signal, the threshold value V TH
is high or low, this causes signal II
I II becomes the signal “0” or the signal “0”
There is no danger that '' will become signal 111 II.

The present invention will be described in detail below with reference to Examples.

FIG. 5 shows the modulation circuit of the measuring device and its vicinity. A serial binary signal 2 supplied from a measuring device (not shown) in a format specified by R8232C etc. is
The signal level is adjusted by the driver 3, and the CPU (
The data processing unit n is supplied to a data processing unit n such as a central processing unit). The same binary signal 2 as manually input by the driver 3 (Figure 6a)
are supplied to the first and second monostable multivibrator 4.5 of the modulation circuit.

The first monosterple multivibrator 4 moves from the rising edge of the signal (from “0” of the binary signal 2 to II I 11
The rising edge detection signal 6 (FIG. 6b) is output from its output terminal Φ.

The second monostable multivibrator 5 detects the falling edge of the signal (the point of change from 1'' to "O" in the binary signal 2), and outputs a falling detection signal 7 from its output terminal Φ.
(Figure 6C) is output. These detection signals 6.7 are input to a logic gate 8, and a gate output signal 9 (FIG. 6d) in the form of a logical sum of rectangular waves is created. Gate output signal 9 is the third monostable multivibrator 2
+tt is supplied to 2, and a rectangular wave is created with the falling point as the starting point. The pulse width of this square wave is 1~
The output (3! is set equal to the pulse width of f30).

A negative rectangular wave signal 23 output from the output terminal Φ of the third monostable multivibrator 22 (the signal is inverted by the first inverter 24 and becomes a positive rectangular wave signal 25. ~The output signal 9 is inverted by the second inverter 26 and becomes a negative square wave signal 2.
It becomes 7. These signals 25,27 are combined to form a recording signal 28 (FIG. 6C). The recording signal 28 is supplied to a chip recorder (not shown) and is also recorded on a recording magnetic tape.

FIG. 7 shows the vicinity of the demodulation circuit.

A reproduced signal 32 output from the tape recorder is supplied to a signal detection circuit 33 via a digital relay.

The reproduced signal 32 obtained from the recording magnetic tape has high and low frequency components removed, and is an analog signal with ringing. For the recording signal 28 not shown in FIG. 6e, a reproduced signal @32 having a waveform as shown in FIG. 8a is obtained. As already explained, at the change point of the binary signal 2, a rectangular wave symmetrical to the baseline is generated. Therefore, the direction in which ringing is generated is always the same, and is the direction in which the first half of the point-symmetric rectangular wave is generated. In FIG. 8a, the downward direction is the direction in which ringing 32R occurs.

The signal detection circuit 33 sets a threshold value V□ in the direction opposite to the direction in which linking occurs with respect to the baseline of the reproduced signal 32. Threshold value V□, is reproduction signal 3
The detection range of 2 can be freely set. The signal detection circuit 33 outputs a detection signal 34 when the reproduced signal 32 exceeds the threshold value VTH. The detection signal 34 is J,
It is input to the Noritsubu flop circuit 35 and its output terminal Q
A serial binary signal 36 (FIG. 8b) is output from.

By the way, in J, the flip-flop circuit 35 has each i
n (Prior to the reception of the serial binary signal 2 of i7, a clear signal 37 is supplied, and its contents are cleared. Then, for example, a detection signal 37!I that detects a synchronization signal ``1'') is supplied and reproduced. This signal “
'1 is followed by a serial binary signal 36 to, for example, 8 bits 1, so these signals are the signal "o"
and the signal “1'' is played in reverse.
The forward signal 36 is comprised of signals ``0'' and ``1''.
Since the time width is accurately reproduced, there is no need to synchronize with a playback clock.

The binary signal 36 is supplied to one input terminal 11 of a switching circuit 38 . The other input terminal I2 is connected to the receiver 39.
: Another serial binary signal 42 received is supplied. The switching circuit 38 selectively selects these binary signals 36 and 42 according to the selection signal 43,
It is output as selection data 44. Selection data 44 is CP
It is supplied to a data processing device such as LI.

As explained above, according to the present invention, a monostable multivibrator is triggered by each rising edge and falling edge of a serial binary signal, and the signals are combined to create a recording signal. Therefore, by adjusting the threshold value VTH for detecting the signal "1", it is possible to obtain a good binary signal that is not affected by waveform distortion.

Further, the present invention provides a method for detecting the rising edge or rt of a reproduced waveform.
For example, at the bottom of J, set the flip-flop circuit to 1.
It is reproducing a binary signal. Therefore, the signal “1”
The width of ``'' does not matter, but the spacing between them does. Therefore, a stable output can be obtained, and it is possible to use a cheap radar or magnetic tape with a narrow band.

In addition, the transfer speed can be achieved up to 4800 BPS (pills per second) using a combination of ordinary recording magnetic tape and a tape recorder, and higher speeds can be achieved by selecting magnetic tape and a tape recorder. It is possible.

[Brief explanation of drawings]

Figures 1 to 4 are for explaining the conventional recording/amplifying system, of which Figure 1 is a waveform diagram of a modulation signal according to the Conley City Standard system, and Figures 2 and 3 are a waveform diagram of a modulation signal based on the Support 1 recording system. "A waveform diagram of a modulated signal according to the City Standard system, FIG. 4 is a waveform diagram of a binary signal and modulation No. 18 in a system using two channels, and FIGS. 5 to 8 illustrate an embodiment of the present invention. Figure 5 is a block diagram showing the modulation circuit and its vicinity;
FIG. 6 is a diagram of various waveforms to explain the operation of the modulation circuit.
Figure 7 shows the demodulation circuit and its vicinity.
8 are various waveform diagrams for explaining the operation of the demodulation circuit. 2.36...Binary signal 4...First monostable multivibrator 5...Second Enostable multivibrator 8... Logic gate 22...Third monostable multivibrator 24...First inverter 26...Second inverter 33...Signal detection circuit 35・・・・・・J, for flip-flop circuit
Patent attorney representing Japan Atomic Energy Corporation Umeo Yamauchi

Claims (2)

[Claims] 1. It is characterized by modulating a binary signal into a rectangular wave that is point symmetrical with respect to the baseline at each change point of the signal, and recording this modulated signal on a recording magnetic tape and playing it back. Recording/playback type of magnetic tape for recording. 2. A binary signal is modulated into a rectangular wave that is symmetrical with respect to the baseline at each change point of the signal, and a magnetic tape is used to record this modulated signal, and an analog signal is reproduced from this tape. A binary signal in which a threshold value is set at a predetermined level with the baseline of the signal as the M quasi, the rising or falling edge of the analog signal is detected using this threshold value, and the signal level is changed using this detection signal. A method for recording and reproducing magnetic tape for recording, which is characterized in that it creates a 71R binary signal and converts it into a binary signal.