JPS63155404A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To simplify a recorded detecting circuit by using in common a video head driving use recording amplifier having a magnetic recording circuit, as a read reproducing signal amplifier of the recorded detecting circuit. CONSTITUTION:The output of a mixing circuit 3 is inputted to a recording amplifier 4 through a changeover switch 15, the output of the recording amplifier 4 is inputted to a magnetic head 5 through a switch 16, the output of a level amplifier 12 is provided to the other input of the changeover switch 15, and the output of an internal amplifying signal of the recording amplifier 4 is inputted to an integral amplifier 13. The changeover switch 15 and the switch 16 are interlocked and switched by a system controller 10. Accordingly, as for a recorded detecting circuit, the recording amplifier 4 can be utilized as an amplifier, the circuit scale is miniaturized, and also, the number of parts can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording/reproducing device, particularly to a recorded detection circuit for a still video camera.

- Background of the Invention - Magnetic recording and reproducing devices such as still video cameras are equipped with a recorded detection circuit that detects the presence or absence of recording on each track of a magnetic sheet so that recording can be performed while avoiding recorded tracks when recording one image signal. 0 For example, in a still video camera, frame images of a subject are read out from an image sensor through an optical system, these frame images are concentrically recorded on a magnetic sheet as video signals, and the reproduced images can be displayed on a television, etc. However, recording that avoids the B&magnetic sheet recorded tracks prevents previously recorded images from being accidentally erased.

FIG. 2 shows the configuration of a recording circuit and a recorded detection circuit of a still video camera. The luminance signal Y+S including the synchronization signal S is FM-modulated by the luminance signal modulation circuit 1, the line-sequential color difference signal R-Y/B-Y is FM-modulated by the color-difference signal modulation circuit 2, and the output of the re-modulation circuit 1.2 is Mixed by the mixing circuit 3 and supplied as a recording current to the recording/reproducing head 5 via the recording amplifier 4, the magnetic sheet 6 (floppy disk)
The recorded data is recorded on the positioned track. This recorded signal is
The signal is read out from the head 5 to the reproduction amplifier 7 side, and is reproduced by the reproduction circuit 8 to be taken out as a video signal. The magnetic sheet 6 is rotated at a constant speed by a motor 9, and the speed control of the motor 9, the position control of the head 5, etc. are controlled by a system controller 10 made up of a microcomputer. The recorded detection circuit 11 amplifies the RF@ signal reproduced by the reproduction amplifier 7 with a level amplification circuit 12, then integrates and amplifies it with an integrating amplifier 13, and compares it with a reference voltage with a level comparison circuit 14 to obtain an RF signal. In other words, a recording detection signal is obtained. When this signal includes a recording presence signal, the system controller 10 moves the helad 5 to the next track and waits for detection of recording presence/absence again.

Problems to be Solved by the Invention In the Q-completed detection circuit 11, the head output voltage is 2.
00 to 300 JLV is amplified by the reproduction amplifier 7, the reproduction RF signal is converted into a DC component by the level amplifier 12 and the integrating amplifier 13, and compared by the level comparison circuit 14.

Therefore, the amplification gain of the entire recorded detection circuit is approximately 8
The configuration of such a high-band, high-gain amplifier circuit, which can range from 0 to 100 dB, requires several stages of amplifiers, which poses a problem of increasing the size of the circuit and the number of components.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a magnetic recording/reproducing device that can simplify the recorded detection circuit.

Means and Effects for Solving the Problem The present invention focuses on the fact that image recording and recorded detection are not performed at the same time, and uses a video head drive recording amplifier included in the magnetic recording circuit as a recorded detection circuit. The configuration is such that it is shared as a read and reproduced signal amplifier, so that the total amplification degree as a recorded detection circuit can be reduced.

-Embodiment- FIG. 1 is a circuit diagram of a main part showing an embodiment of the present invention. The difference between this figure and FIG. 2 is that the output of the mixing circuit 3 is input to the recording amplifier 4 via a changeover switch 15, and the output of the recording amplifier 4 is input to the magnetic head 5 via a switch 16. A level amplifier 1 is connected to the other input of the switch 15.
2, and the internally amplified signal output of the recording amplifier 4 is input to the integrating amplifier 13. Changeover switch 1
5 and switch 16 are linked to the system controller 10.
Switched by.

In such a configuration, when recording a video signal, the selector switch 15 is switched to the mixing circuit 3 side, and the switch 16 is switched to the mixing circuit 3 side.
is closed and recording is performed through switches 15 and 16. In contrast to this recording mode, in the recorded detection mode, the selector switch 15 is switched to the level amplifier lz side, and the switch 16 is opened, and playback from the RAD 5 to recording is performed. The signal is led to the integrating amplifier 13 via the path of the reproducing amplifier 7, the level amplifier 12, the switch 15, and the recording amplifier 4, and then the level comparing circuit 14.
Detects whether or not it has been recorded.

Therefore, in the recorded detection circuit, the recording amplifier 4 can be used as an amplifier, and the amplification degree of the level amplifier 12 etc. can be made small, that is, the circuit scale can be made small and the number of parts can be reduced to obtain a sufficient amplification degree. It is possible to create a circuit configuration with a bandwidth of

In the embodiment, a case has been shown in which the present invention is applied to a still video camera that also has a playback function, but the present invention is not limited to this. It goes without saying that the present invention can be applied to other magnetic recording and reproducing apparatuses to obtain similar effects.

Effects of the Invention As described above, according to the present invention, since the recording amplifier of the recording circuit is used as an amplifier for reproducing and amplifying the RF signal of the recorded detection circuit, the circuit scale and number of components of the recorded detection circuit can be reduced. This has the effect of reducing the amount of electricity.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a main part showing an embodiment of the present invention, and FIG. 2 is a circuit diagram of a recording circuit and a recorded detection circuit of a conventional magnetic recording/reproducing apparatus. 3...Mixing circuit, 4...Recording amplifier, 5...Magnetic head, 6...Magnetic sheet, 7...Reproducing amplifier. 8... Regeneration circuit, lO... System controller,
11... Recorded detection circuit, 12... Level amplifier, 13... Integrating amplifier, 14... Level comparison circuit,
15... Selector switch, 16... Switch. Patent applicant Konishiroku Photo Industry Co., Ltd. Figure 2

Claims (1)

[Claims] 1) A magnetic recording and reproducing device equipped with a recorded detection circuit, characterized in that a recording amplifier for driving a video head included in the magnetic recording circuit is also used as a reading and reproduction signal amplifier of the recorded detection circuit. .