JPS61224583A - Still picture reproducing device - Google Patents

Abstract

PURPOSE:To make it possible to delay a reproducing FM signal of wide frequency band with an existing delay circuit by converting the reproducing FM signal to an FM signal with a high carrier-frequency at a frequency conversion circuit and making the frequency-modulated high frequency FM signal to delay for 0.5 horizontal period at the delay circuit. CONSTITUTION:A reproducing FM signal which is reproduced from a rotary magnetic disk 1 by a reproducing head 2 is inputted to the one side of the input terminal of a frequency conversion circuit 12 and a signal with a single frequency f0 from a reference signal source 11 is inputted to the other side of the input terminal and from the frequency conversion circuit 12, the reproducing FM signal of the difference frequency of these two signals is outputted. In the period that the picture of the second field is reproduced, the high frequency reproducing signal that is delayed for 0.5 horizontal period at a delay circuit 4 is inputted to a video signal demodulating circuit 6 and by demodulating the signal, a video signal of the second field is obtained. Assuming that the carrier-frequency of the reproducing FM signal that is made to delay at the delay circuit 4 is 14mHz, the passband of the delay circuit 4 is enough to be 14+ or -4mHz.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a so-called electronic camera that captures and records still images using, for example, a COD imaging device and a magnetic disk. The present invention relates to a still image playback device that plays back images.

[Conventional technology]

Conventionally, there has been a device of this type as shown in Figure 1g3. In the figure, (υ is a magnetic disk that rotates at a field period (for example, 60 Hz), and one circular track contains video signals for one field at a center frequency of, for example, 7 MHz.
z, band 1! It is recorded as an i 4 MB2 OF M signal. (2) is a playback head, which is a magnetic disk tl.
Play the video signal from J. (3) is an amplifier circuit that amplifies the reproduced video signal (hereinafter referred to as the reproduced FM signal); (4)
is a delay circuit that delays the input signal for 0.5 horizontal period, (6
) is a switching circuit, one fixed contact (5a) is input with an amplified reproduced FM signal, and the other fixed contact (5b) is input with a reproduced FM signal delayed by 0.5 horizontal period. (6) is a video signal demodulation circuit that demodulates the reproduced FM signal input from the movable contact (5C) of the switch (5) into a video signal, and (7) is the input signal for the demodulated video signal to the monitor α◆. The video signal processing circuit (8) is a bus generator that outputs one timing pulse every time the magnetic disk (1) rotates, and this timing pulse is used as a reproduction FM signal.
It is output at field intervals in synchronization with the reproduction timing of the recording start and end of the signal. (9) is an amplifier circuit, and (9) is a switching signal generation circuit, which sends out a switching signal with a field period synchronized with the timing pulse.
) is switched between one fixed contact (5a) and the other fixed contact (5b) in synchronization with the recording start and end of reproduction FMll1.

Next, the operation will be explained.

One field of reproduced FM signal reproduced from the magnetic disk (13) by the reproduction head (2) is transmitted to the amplifier circuit (3).
It is amplified by one fixed terminal (5a) of the switch (5) and is inputted to the other fixed contact (5b) via the delay circuit (4) t- with a horizontal period of 0.5H.

During the first field, the movable contact (5C) of the switch (5)
is connected to the fixed contact (5a), and the reproduced FM signal output from the amplifier (3) is demodulated by the video signal demodulation circuit 16, and then converted into the first field video signal by the video signal processing circuit (7). The first field screen is displayed on the monitor α◆.

Next, the switching signal is transmitted from the switching signal generation circuit to the switching circuit (
5), the movable contact (5C) is connected to the fixed contact (5b
), the same FM playback signal delayed by 0.5 horizontal period from the delay circuit (4) is input to the video signal demodulation circuit (6), undergoes similar signal processing, and displays the second field on the monitor α◆. screen will be displayed.

This kind of operation is repeated nine times, so monitor A4
displays an interlaced still image.

[Problem that the invention seeks to solve]

By the way, in the conventional device described above, it is possible to use a glass delay line for the delay circuit (4). However, in order to obtain a good image, it is necessary to widen the bandwidth of the reproduced FM signal that has passed through the delay circuit. but.

It is difficult to manufacture a delay circuit with a center frequency of 7 MH2 and a bandwidth of ±4 MHI using a glass delay line, and it is expensive.

This invention was made in order to eliminate the drawbacks of the prior art as described above.
An object of the present invention is to obtain a still image reproducing device which performs M signal delay.

[Means for solving problems]

The still image playback device according to the present invention includes a frequency conversion circuit that converts a playback FM signal into a playback FM signal with a higher frequency than the original carrier frequency, and delays the high-frequency converted playback FM signal by 0.5 horizontal period in a delay circuit. This feature is characterized in that it allows the user to

[Effect]

In this invention, the frequency of the reproduced FM signal is frequency-converted from the original carrier frequency to a high-frequency reproduced FM signal by the frequency conversion circuit, and the high-frequency converted reproduced FM signal is delayed by the delay circuit, so that the carrier frequency is high. Accordingly, the passband width of the delay circuit becomes wider, making it possible to achieve a wider band of the delay circuit and, by extension, higher image quality.

[Embodiments of the invention]

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

In the figure, αυ is the music frequency f, <for example 21 M
Uta, a reference signal source that generates Hz), inputs the reproduced FM signal and the reference signal from the reference signal source αη, and outputs an FM signal with a frequency that is the difference between the two frequencies (14 MHz in this example). This is a frequency conversion circuit.

Next, the operation will be explained.

The reproduced FM signal (center frequency 7 MHz) reproduced from the rotating magnetic Dinuk (1) by the reproduction head (2) is input to one input terminal of the frequency conversion circuit ■ via the amplifier circuit (3), and the other input terminal is input to the frequency conversion circuit ■. A signal with an olfactory frequency fo (center frequency 21 MHz) from the reference signal source αυ is input to the terminal, and a reproduced FM signal with a difference frequency (center frequency 14 MHz) between the two signals is output from the frequency conversion circuit @. Ru.

During the period when the first field image is being played back, the switch (5
) is connected to the fixed contact (5a) by the switching signal sent from the switching signal generation circuit αq, and the video signal demodulation circuit (6) receives this high frequency converted and reproduced FM signal. is input and demodulated to obtain the first field video signal. This is the video signal processing circuit (
7) and displayed as the first field screen on the monitor σ.

Next, during the period when the image of the second field is being reproduced, the movable contact (5C) of the switch (5) is connected to the other fixed contact (5b) by the switch signal, and the video signal demodulation circuit (6) A high-frequency reproduced old code delayed by 0.5 horizontal period is input to the delay circuit (4), and this is demodulated to obtain a second field video signal. This is the video signal processing circuit (7)
is processed and displayed as a second field screen on monitor α4.

As these operations are repeated alternately, monitor α
Similar to the conventional apparatus described above, an interlaced still image is obtained in ◆.

In this embodiment, the reproduced FM signal is delayed by the delay circuit (4).
Since the carrier frequency of the @ signal is 14 MHz, the passband width of the delay circuit (4) may be 14±4 MH2. Such a delay circuit (4) can be manufactured relatively easily using a glass delay line that has been used in the past, so a wide band can be easily realized, and a still image reproducing device with good image quality can be obtained.

FIG. 2 is a block diagram of another *m example of the present invention, in which only the FM reproduced signal with a carrier frequency of 7 MHz to be delayed is converted into an FM signal with a carrier frequency of 14 MHz by the first frequency converter circuit, and then the delay circuit (4 ), and then the second frequency conversion circuit (to) returns the original carrier frequency (7M
Hz), the switching circuit (6) alternately switches each field one field at a time, and displays the signal on the A4 screen after passing through the video signal demodulation circuit (6) and the video signal processing circuit (7). be.

In this embodiment as well, the delay circuit (4) can be constructed of a glass delay line, and the same effects as in the embodiment shown in FIG. 1 can be obtained.

In the above embodiment, an example was shown in which a magnetic disk was used as the record carrier, but it can be similarly applied to still image reproduction from an optical disk, and similar effects can be obtained. [Effects of the Invention] As described above, this According to the invention, a reproduced FM signal is converted into an FM signal with a high carrier frequency by a frequency conversion circuit, and this frequency-converted high-frequency FM signal is delayed by 0.5 horizontal period by a delay circuit, which is different from conventionally used FM signals. Do you have a similar glass delay line? A wide-band delay circuit can be constructed using the same method, and an inexpensive still image reproducing device with good image quality can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a still image reproducing apparatus according to one embodiment of the present invention. FIG. 2 is a block diagram of another embodiment of the present invention, and FIG. 3 is a block diagram of a conventional still image reproducing apparatus. (υ...magnetic disk, (2)...playback head, (
3)...Amplification circuit, (4)...Delay circuit, (5)...
...Switcher, (6)...Video signal demodulation circuit, (7)...
...Video signal processing circuit, (8)...Pulse generator, (
9J-...Amplification circuit, OQ-...Switching signal generation circuit, α
p... Reference signal source, O, aa... Frequency conversion circuit. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] (1) One field of the video signal recorded on the recording medium is repeatedly reproduced, the first field's reproduced video signal is sent out at the original phase, and the second field's reproduced video signal is 0.5 horizontal In a still image display device that is configured to alternately repeat the operation of transmitting the video signal with a phase delayed by a period of time, demodulate these video signals, and display them on a monitor, at least the carrier frequency of the reproduced video signal of the second field is means for converting the frequency to a higher frequency than the original carrier frequency, and a delay circuit for converting the frequency-converted reproduced video signal to a frequency higher than the original carrier frequency.
5. A still image reproducing device, comprising: means for delaying by five horizontal periods. (2) means for converting the reproduced video signals of the first and second fields to a carrier frequency higher than the original carrier frequency; means for delaying the frequency-converted reproduced video signals of the second field by 0.5 horizontal period; 2. The still image display device according to claim 1, further comprising means for demodulating the delayed frequency-converted reproduced video signal of the second field to the original carrier frequency.