JPS6190364A - Magnetic reproduction device - Google Patents

Abstract

PURPOSE:To demodulate relatively wide band signals with a simple circuit by reproducing signals separately from a medium on which two frequency modulated signals of which rise-up and trail edge timings are different from each other, and by demodulating them with combining rise-up and trail edges. CONSTITUTION:Two different signals of which frequencies modulated rise-up and trail edge timings are different from each other are recorded on magnetic tape 1. The signals of tape 1 reproduced by reproduction head 2a, 2b pass through pro-amplifiers 3a, 3b and are detected of their rise-up and trailing edges by rise-up edge detectors 4a1, 4b1, and trail edge detectors 4a2, 4b2. The output signals (c), (d) and (e), (h) issued from the detectors 4a1, 4a2, and 4b1, 4b2 respectively pass through OR gates 5a, 5b and combined signals (g), (h) are inputted to SRFF6, and a signal (i) is inputted to FM demodulator 9 through a reproduction level adjuster 7 and buffer 8, and them FM demodulated signal (j) is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic reproducing apparatus, and more particularly, to a magnetic reproducing apparatus that reproduces video signals, data signals, etc. from a magnetic recording medium on which the signals are frequency-modulated and recorded.

2. Description of the Related Art In recent years, magnetic recording devices such as VTRs and data recorders that frequency-modulate a wideband signal such as a video signal and record it on a magnetic recording medium have become widespread. In this case, the carrier wave frequency generally needs to be higher than the highest frequency of the modulated signal (input signal to be recorded), and is limited to a frequency that can be recorded on the recording medium.

As described above, the band of the modulated signal is limited to the recordable band of the recording medium, and the conventional apparatus has the disadvantage that a wideband signal cannot be freely recorded on a relatively narrowband recording medium.

Therefore, the applicant filed a patent application rti! frequency modulating the input signal and detecting the rising edge and falling edge of this frequency modulated signal, respectively,
Furthermore, we proposed a technique in which the signals obtained by dividing the rising edge and falling edge frequencies are recorded using separate recording heads, thereby making it possible to reliably record a wideband signal onto a relatively narrowband recording medium. In this way, the above-mentioned inconvenience was eliminated.

An object of the present invention is to provide a magnetic reproducing device capable of reproducing signals recorded on a recording medium by the device proposed above.

Means In FIG. 1, reproducing heads 2a and 2b are an embodiment of means for reproducing signals from the magnetic tape 1, and a rising edge detector 4a.
+, 4b+, falling edge detectors 4a2, 4b2 are an embodiment of means for detecting rising edges and falling edges of the reproduced signal; OR gates 5a, 5b, flip-flop 6, FM demodulator 9, etc. are 2 This is an embodiment of a means for synthesizing the rising edges and falling edges of two signals to obtain rising and falling signals at each timing and frequency demodulating the signals.

The rising edge detectors 4a + , 4b + and the falling edge detectors 4az, 4b2 detect the rising edge and falling edge of the reproduced signal, and the OR gates 5a,
5b, a flip-flop 6, an FM demodulator 9, etc., combine the rising edges and falling edges of the two signals to obtain rising and falling signals at each timing, which are MF demodulated.

Embodiment FIG. 1 shows a block system diagram of an embodiment of the apparatus of the present invention. In the figure, signals corresponding to signals a and b (FIG. 2 (A>, (B)) are recorded on a magnetic tape 1 by the aforementioned patent application "Magnetic Recording Apparatus" proposed by the present applicant. This recorded signal is obtained by frequency-modulating the input signal, detecting the rising edge and falling edge of this frequency-modulated signal, and dividing the frequencies of the rising edge and falling edge, respectively. The signals obtained through the rotation are recorded by separate recording heads.

The signals reproduced from the magnetic tape 1 by the reproduction beds 2a and 2b are amplified by the preamplifiers 3a and 3b to produce a signal a.
, b (Fig. 2 (A), (B)), and the signal a is detected by the rising edge detector 4a+ and the falling edge detector 4a2.
A rising edge and a falling edge are respectively detected at , and are converted into signals c and d ((C) and (D) in the figure), respectively, and the signals are sent to a rising edge detector 4b+ and a falling edge detector 4b2. A rising edge and a falling edge are respectively detected and used as signals e and f ((E) and (F) in the figure), respectively.

The signals c and d are ORed by the OR gate 5a and become the signal g.
((G) in the same figure), and on the other hand, the signal e.

f is ORed by the OR gate 5b and becomes the signal h ((
H)), and the signal 0. h is supplied to the S terminal and RDi terminal of the SR flip-flop 6, respectively, and the signal i ((
I)). Signal i is a signal that rises and falls at timings synchronized with the rising edges and falling edges of signals a and b, and is the same as the output of an F fvl modulator in a magnetic recording device.

The signal i is level-adjusted by a reproduction level adjuster 7, and is supplied to an FM demodulator 9 via a buffer 8, where it is FM demodulated to become a signal j ((J) in the same figure), which is sent to an output terminal 10.
taken out from Signal 1 is the same as the input signal in the magnetic recording device, and the original signal is reproduced.

Effects of the Invention The apparatus of the present invention has means for separately reproducing two signals from a magnetic recording medium on which two signals are frequency modulated and have different rising and falling timings, and means for detecting rising edges and falling edges of each of the two signals; and means for synthesizing the rising edges and falling edges of the two detected signals to obtain rising and falling signals for each of the timings of the synthesized edges. Since a means for frequency demodulation is provided, it has the advantage of being able to demodulate a relatively wideband signal recorded separately on a relatively narrowband recording medium into two low frequency signals with a simple circuit.

[Brief explanation of drawings]

1 and 2 are a block system diagram and a signal waveform diagram for explaining the operation of an embodiment of the apparatus of the present invention, respectively. 1... Magnetic tape, 2a, 2b... Playback bed, 4
a+, 411+...Rising edge detector, 4a2゜4
b2... Falling edge detector, 5a, 5b... OR gate, 6... Flip-flop, 9... FM demodulator, 10... Output terminal.

Claims (1)

[Claims] Means for separately reproducing two frequency-modulated signals having different rise and fall timings from a magnetic recording medium recorded with the signals, and a means for separately reproducing two signals having different rise timings and fall timings, and a means for separately reproducing the two signals having different rise timings and fall timings, and means for detecting edges and falling edges, and combining the rising edges and falling edges of the two detected signals to obtain rising and falling signals for each timing of the combined edges and frequency demodulating the signals. A magnetic reproducing device comprising: means.