JPH01168175A - magnetic recording and reproducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic recording/reproducing apparatus such as an electronic still camera or a video floppy recorder player that records video signals as FM signals on a magnetic disk.

2. Description of the Related Art In recent years, there has been active development and commercialization of devices for recording and reproducing video signals on video floppies with a diameter of less than 2 inches. Under these circumstances, development is being carried out to widen the video bandwidth and obtain high-resolution image quality. In order to widen the video band, a method is used to raise the FM carrier frequency. Here, when two formats, a normal image quality format and a high-resolution image quality format, coexist, it is necessary to identify which format is being recorded during playback. - Two formants are given as examples.

FIG. 3 shows a conventional configuration.

Reference numeral 31 is a big off disk on which signals are recorded using FM waves, 32 is a magnetic head for reproducing the recorded signals, and 33 is a head amplifier for amplifying the head output. 34 is an FM demodulation circuit, and 35 and 36 are demodulation low-pass filters. 36 is for normal image use and passes signals with a band of up to 4.5 MHz. 36 is for high resolution and has a bandwidth of 6.5M)h
Pass the signal up to.

37 is a signal selection switch, and 38 is a signal processing circuit that performs processing such as setting a predetermined amplitude. 39 is a video output terminal. 40.41 is a synchronous circuit, F of the synchronous signal section
Tune to M frequency. 40 is a 6MHz tuning circuit, 41
is an 8MHz tuned circuit. A comparator 42 receives the outputs of the tuning circuits 40 and 41 and determines which one is larger.

That is, for a normal image, the output of the tuning circuit 40 is greater than the output of the tuning circuit 41, and the output of the comparator 42 is at the rHJ level, and for a high resolution image, the output of the tuning circuit 41 is greater than the output of the tuning circuit 4o. The output of the comparator 42, which is larger than the output, becomes rLJ level. The image is switched by controlling the signal selection switch 37 using this signal.

Problems to be Solved by the Invention However, the conventional configuration described above has a problem in that the configuration for determining which format is being recorded is complicated.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a magnetic recording/reproducing device with an easy configuration for performing discrimination.

Means for Solving the Problems In order to solve the above problems, the magnetic recording and reproducing apparatus of the present invention includes a limiter means for limiting the frequency modulated FM signal and a digital signal that uses a part or all of the horizontal synchronization period as a window. A wind pulse generating means is provided, a counter means for counting the wind pulse period and the number of waves of the FM signal wave passed through the limiter means, and a comparison means for comparing the count value by the counter means with a predetermined value determined in advance. The structure is as follows.

Effect of the present invention With the above configuration, the FM reproduction signal is passed through a limiter to form a digital waveform, and by counting and comparing the wave numbers of the FM waves, discrimination can be performed digitally, and external parts can be easily integrated into an IC. This makes it easy to create multiple configurations with fewer components.

Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram showing the configuration of the magnetic recording/reproducing apparatus of this embodiment, and FIG. 2 is a waveform diagram for explanation. In Figure 1, 1 is a video floppy disk, 2 is a magnetic head, 3 is a head amplifier, 4 is a limiter, 5 is an FM demodulation circuit, and 6 is a low-pass filter that passes signals in a band up to 4.5 MHz for normal image quality. , Ryo is 8 for high resolution
．． A low-pass filter 8 passes signals in a band up to a 5M ratio, and a selector switch 8 selects between the two signals. 9
1 is a signal processing circuit, and 14 is a signal output terminal. 1o is a synchronization separation circuit, and 11 is a wind pulse generation circuit as shown in Figure 2H.
As shown in FIG. 2, a pulse with a width of, for example, 1.0 M seconds is generated from T microseconds after the leading edge of the horizontal synchronizing signal. 13 is a counter which counts the limiter output signal shown in FIG. 2 (6:I) during the period of the wind pulse. In the case of a normal image, the FM frequency of the synchronous part of Fig. 2-) is 8M)lz and 180
If there are 6 pulses between pulses of M seconds, the counter advances by 6. Also.

In the case of high resolution, the counter advances by 8 in this case at an 8M ratio. Therefore, if you reset the counter at the leading edge of the wind pulse, the counter output will be ``6'' in the case of 1 normal image quality and 08'' in the other case, and the preset value will be
(If it is 7", you can easily tell whether it is a normal image or a high-resolution image by comparing it with this 'ゞ7.

In the former case “60”, in the latter case “s o”
Even if noise is mixed in due to side pressure output, etc., it can be easily compared in size with the set value 7o. A comparison circuit 12 compares the value of the counter 13 with the set value as described above, outputs the result, and switches the switch 8. Image discrimination and output selection are performed as described above.

Effects of the Invention As described above, according to the present invention, a wind pulse is generated, the wave number of an FM signal is counted during the period, and this counter value and a predetermined configuration can be used to easily create a digital circuit such as a gate array. It can be composed of I
It becomes easier to convert to C.

Fewer external parts are required.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a magnetic recording/reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a waveform diagram of the same embodiment, and FIG. 3 is a conventional block diagram. 4...Limiter, 11...Wind pulse generation circuit, 10...Synchronization separation circuit, 12...
...Comparison circuit. 13...Counter.

Claims (2)

[Claims] (1) A magnetic recording and reproducing device that reproduces a frequency-modulated video signal, including a limiter means that limits the frequency-modulated FM signal, and a wind pulse generation means that extracts part or all of the horizontal synchronization period as a window. and counter means for counting the wave number of the FM signal passed through the limiter means during the window pulse period, and comparison means for comparing the count value by the counter means with a predetermined value determined in advance. A magnetic recording/reproducing device characterized by discriminating types. (2) A patent claim characterized in that the comparing means includes means for counting the wave number of the FM signal over a window period of a plurality of horizontal synchronization periods, and compares the average value with a predetermined value determined in advance. The magnetic recording and reproducing device according to item 1.