JPH02134705A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To adjust the optimum recording level and the recording frequency characteristic or the like during the recording of a signal without provision of a reproducing head by throwing plural switch circuits changing over the connection of a rotary head, a recording circuit and a reproducing circuit to the position of the recording and the reproducing circuit for each revolution of the rotary head. CONSTITUTION:A magnetic tape is stopped and switches Sw5 - Sw9 with a timing signal from a switch logic generating circuit 9 for each revolution of a rotary drum D. At first a recording and reproducing head H1 records modulated information. In this case, a recording and reproducing head H2 do nothing and the head H1 reproduces recorded information succeedingly. Then the head H2 records a signal of a single frequency oscillated from an oscillation circuit 8 to erase the information recorded by the head H1. The operation above is repeated alternately, the signal at output terminals TP2,TP1 is observed to attain the adjustment with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording and reproducing apparatus such as a video tape recorder (VTR) for broadcasting stations, commercial use, or consumer use.

[Conventional technology]

Magnetic recording and reproducing devices are classified into several types depending on the differences in recording and reproducing methods and the type of recording medium used. Of these, the E1 is the one that is most widely put into practical use. Recording both video and audio signals using magnetic tape,
This is a V'T''R (video tape recorder) that plays.

Therefore, VTR will be explained below as an example.

A conventional VTR will be explained with reference to FIG. Figure 4 is a block diagram showing the main circuit configuration of the conventional V ``T'' R1, and as shown, it is roughly divided into a recording system (recording signal processing system) and a reproduction system (reproduction signal trapping system). There is. The recording system includes a modulation circuit 2 for FM modulating an input signal and a recording circuit 3. - 1 etc. are provided, and the reproduction system is provided with a reproduction circuit 5.6 and a demodulation circuit 7 for modulating the reproduction signal with FMlgi. Note that H, H2 are rotary heads for both recording and playback (hereinafter also referred to as "recording/playback heads"),
(also referred to as "playback head"). Recording/playback head H1, H2
Recording and playback are switched by Noah changeover switch SWI, 3w2. In addition, 3w3 reproduces the normal reproduction operation and simultaneous reproduction (reproduces the signal immediately after being recorded while recording on the magnetic tape. Therefore, at this time, the selector switch Sv
, is also connected to contact blPI. ) operation is a changeover switch Sw for changing over the EE operation (monitoring the signal to be recorded) and the playback operation (playback from the magnetic tape). The conventional VTR 1 is configured like this (the specific circuit, V1 structure, etc. are not directly related to the gist of the present invention, so
(Illustrations and explanations are omitted) Therefore, a playback output can be obtained even during recording, and by monitoring this signal with a display device such as CR'I'', the optimum recording level can be adjusted without repeated adjustments. In addition, some recording frequency characteristics can also be observed at the same time.

[Problem to be solved by the invention]

However, the conventional VTRI configuration described above has a problem in accurately adjusting the recording frequency characteristics. The cause of this is the recording/reproducing heads H1, H2 and the reproducing circuit 5 during normal playback, and the reproducing head 13. during simultaneous playback. This is because there is a mismatch in characteristics between H& and the reproduction circuit. In addition, in the conventional VTR 1, from the point of view of the function of enabling i+lPi such as frequency characteristics while recording signals, extra playback heads H3 and H4 are required, and the configuration of the playback circuit 6 is also changed. There is also the disadvantage that it leads to an increase in expenses.

[Means to solve the problem]

A magnetic recording and reproducing apparatus of the present invention includes a rotary head for recording and reproducing, a recording circuit, a reproducing circuit, and the rotary head and the recording circuit in a recording mode and a reproducing mode.

A plurality of switch circuits each switching the connection of the reproduction circuit,
By configuring these switch circuits with a control signal generation circuit that generates a control signal for switching to the recording side or the reproduction side every rotation of the rotary head, the drawbacks of the conventional device described above can be solved and the reproduction The optimum recording level, recording frequency characteristics, etc. can be adjusted accurately during signal recording without installing a head.

〔Example〕

The basic principle of the magnetic recording and reproducing apparatus of the present invention will be explained with reference to FIG. The magnetic tape T is stopped, and one recording/reproducing head (1-
By alternately repeating recording and reproduction for i, or H2>, the same function as simultaneous reproduction in conventional devices is provided.

The case shown in Figure 2 is an example of recording and reproducing on the CIIH channel 1) side of a so-called two-head type Vi'H (that is, an example of alternately repeating recording and reproducing using only the recording/reproducing head H1). In this case, the recording/playback head H.

A reproduction signal corresponding to 0.5 rotations is obtained for every two rotations of (rotary drum D).

Next, a specific embodiment of the magnetic recording/reproducing apparatus of the present invention will be described using a VTR as an example with reference to the accompanying drawings. FIG. 1 is a block diagram showing the main parts of a VTR10 which is an embodiment of the present invention, and in this figure,
Components that are the same as those of the conventional device 1 shown in FIG. 4 are given the same reference numerals, and detailed explanation thereof will be omitted. V'T' of the present invention
The main feature of the RIO is that, as is clear from a comparison between FIG. 1 and FIG. 4, a read-only head can be omitted, and therefore the reproducing circuit 6 is also unnecessary. In addition, 8 is an oscillation circuit, 9 is switches, and the switch logic generation date I! for generating switching control signals for the switches. 8 (control signal generation circuit), and the components other than this switch logic generation circuit 9 are conventional V
It can be constructed using well-known components in TR, but furthermore, 4::,,:
It has two adjustment modes (C1ll recording/playback mode and C112 recording/playback mode).

Next, the functions and operations of the VTR 10 of the present invention will be explained with reference to the signal waveform diagram (timing chart) of FIG. In addition, each changeover switch Sw5 in FIG.
In Swg, the control signal ■ from the switch logic generation circuit 9 to each changeover switch S 1v 5 to Swg
When ~ ■ is L (Low), H (I
Iigt+), it shall be connected to the contact side marked 0.

First, the normal mode will be explained. When monitoring the input signal via the modulation circuit 2 and demodulation circuit 7 (rE
(abbreviated as E), the control signal to the changeover switch Sw5 becomes L, and becomes I4 during reproduction. Also, the control signals ■ and ◎ to the changeover switches SW6 and SW7 are always on, and the control signals ■ and ◎ to the changeover switches SXv8 and Swg are
(2) is set to H during recording, and set to I- for other times. As a result, the changeover switches Sw5 to Swg are switched to contact a (EE
) or b (reproduction).

It is connected to the b, b, a (recording) or b (reproducing), a (recording) or b (reproducing) side, and operates in the same way as the conventional V'r'R1.

Next, the operation and operation in the adjustment mode will be explained. FIG. 3 shows the waveforms (high and low levels) of each of the control signals ① to ② in this mode.

The figure (2) shows the state when the recording/reproducing head H is in contact with the magnetic tape T (see Fig. 2) attached over 180 degrees to the circumferential surface of the rotating drum D. (, recording/reproducing head 112
The figure shows 1- when the two are in contact with each other. Below, the operation to switch to the C111 recording/playback mode (recording/playback mode when the recording/playback head H1 is used for recording and reproducing information signals) (the signal waveforms of control signals ■ to ■ are (8) to (E) ) will be explained.

Section (a)>: recording/reproducing head H, modulated information 18
Record the issue. The recording/playback header H2 does nothing.

The output is EE output.

Section (b) > : Neither the recording/reproducing heads H, , H2 do anything, and the output is EE output.

Section (C)>: The recording/reproducing head I-(1 reproduces the information signal recorded in section (a). The recording/reproducing head I-12 does nothing. The output becomes the reproduction output.

Section (d)>: The recording/reproducing head H1 does nothing. The recording/reproducing head Fr 2 records a single frequency signal generated by the oscillation circuit 8 . This is to erase the information signal j, 1: written in section (a) (same principle as the rotary erasing head in a general VTR), and thereby it is possible to prevent errors due to overwriting.

Section (e)>: This is the same operation as in section (a), and the operations in sections (a) to (d) are repeated below.

The location of the C112 recording/playback mode is shown in the figure (') to (J).
Changeover switch 5W5SW8 at the timing shown in
and Svg are switched, changeover switches S~v6 and 3w
As for 7, does the contact point to be connected change?The operating principle is the same as C111 above.
Since this is the same as in the recording/playback mode, a detailed explanation of the operation will be omitted.

In the above adjustment mode, the output terminal TP3 is
period (in the case of C111 recording/playback mode, the interval (C1, (G
)), and by observing the signal at the output terminal TP2, the optimum notation j, L level can be easily adjusted.
Furthermore, the recording frequency characteristics can be easily adjusted by observing the signal at the output terminal TP. However, since signals are recorded and reproduced using the same recording/reproducing head, it is possible to perform adjustments with much higher precision than in the conventional v'VR.

Figure 5 shows a switch logic generation circuit 9 for generating control signals.
FIG. 2 is a specific circuit configuration diagram. As shown in this figure, manual switch Sw, D free lag frog [[, exclusive OR circuit XOR, ~XORm, AND circuit A circuit A1 and A
It is composed of three inverters 11, etc.

The specific operation of this switch logic generation circuit 9 can be easily understood from the timing chart shown in FIG. 3, so a description thereof will be omitted.

〔effect〕

Since the magnetic recording/reproducing apparatus of the present invention is configured as described above, it eliminates the above-mentioned drawbacks of the conventional apparatus, and can easily adjust the optimum recording level, recording frequency 1, and ν property with very high precision. It has an excellent feature that a read-only head is not required and that it can be realized relatively easily by simply adding a changeover switch and a control No. 12 generation circuit.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the main parts of the magnetic recording/reproducing device of the present invention, FIG. 2 is a principle diagram for explaining the basic operation of the device of the present invention, and FIG. 3 is an adjustment mode for the device of the present invention. FIG. 1 is a block configuration diagram showing the main parts of the conventional device, and FIG. 5 is a specific circuit configuration diagram of a switch logic generation circuit for generating control number 18. 2... Modulation circuit, 3, 11... Recording circuit, 5.6.
... regeneration circuit, 7 ... demodulation circuit, 8 ... oscillation circuit,
9... Switch logic generation circuit, 1o... Magnetic recording/reproducing device (VTR), H+, H2... jA re-hendo, SWI to SW9... Changeover switch, 'r
···Magnetic tape. Patent applicant: Kunio Umiki, representative of Victor Japan Co., Ltd.

Claims (1)

[Claims] A rotary head for recording and reproducing, a recording circuit, a reproducing circuit, and a plurality of switch circuits for respectively switching connections of the rotary head, the recording circuit, and the reproducing circuit between recording mode and reproduction mode, and the plurality of switches Connect the circuit to one of the above rotating heads.
1. A magnetic recording and reproducing device further comprising a control signal generating circuit that generates a control signal for switching to a recording side or a reproducing side every rotation.