Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
1995-05-12
2001-09-04
Vincent, David R. (Department: 2661)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C386S349000
Reexamination Certificate
active
06285821
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a television receiver with a video tape recorder integrally incorporated therein, the video tape recorder having recording and reproducing functions.
2. Description of the Related Art
In order to respond to various consumer needs due to recent increases in variety of life-style, a television receiver with a video tape recorder, which has recording and reproducing functions and is integrally incorporated therein, is becoming widespread.
Generally, such a television receiver with a video tape recorder has a configuration shown in FIG.
2
.
A common terminal c of an external-input changeover switch
22
which functions as an external input terminal of a video tape recorder
21
is connected to a video signal recording circuit
25
and to one input terminal (R/EE terminal) a of a first changeover switch
24
, via an automatic gain control (AGC) circuit
23
which adjusts the level of an input signal to a constant value. The output of a video signal reproducing circuit
26
is connected to the other input terminal (P terminal) b of the first changeover switch
24
.
The video signal recording circuit
25
is a block which records a video signal on a recording medium
27
such as a video tape loaded into the video tape recorder
21
. The video signal reproducing circuit
26
is a block which reproduces a video signal recorded on the loaded recording medium
27
.
An external input terminal
32
to which a separate video tape recorder (not shown) or the like is to be connected is connected to one input terminal a of the external-input changeover switch
22
. A radio frequency (RF) input terminal
28
to which a television antenna (not shown) or the like is to be connected is connected to the other input terminal b of the external-input changeover switch
22
, via a tuning circuit
29
, an intermediate frequency (IF) amplifier circuit
30
, and a detection circuit
31
.
A common terminal c of the first changeover switch
24
is connected to a television signal processing circuit
33
. A video signal output of the television signal processing circuit
33
is supplied to a cathode ray tube (CRT)
34
, and an audio signal output of the circuit to a loudspeaker
35
.
In the thus configured television receiver with a video tape recorder, when a video signal reproduced from a recording medium such as a video tape by the separate video tape recorder connected to the external input terminal
32
is to be input, the common terminal c of the external-input changeover switch
22
is connected to the input terminal a of the changeover switch
22
. Also, the common terminal c of the first changeover switch
24
is connected to the input terminal a of the changeover switch
24
.
As a result of the connection, the video signal reproduced by the separate video tape recorder is supplied via the external input terminal
32
and the terminals a and c of the external-input changeover switch
22
, to the AGC circuit
23
. The input signal is adjusted so as to have a constant level at which the signal can be recorded, and then supplied to the video signal recording circuit
25
and the input terminal a of the first changeover switch
24
.
When the video tape recorder
21
is in the recording mode (dubbing mode), therefore, the video signal reproduced by the separate video tape recorder is recorded on the loaded recording medium
27
.
Whether the recording mode is set or not, the reproduced video signal is supplied to the television signal processing circuit
33
via the terminals a and c of the first changeover switch
24
, to be subjected to a predetermined process. The processed signal is then supplied to the cathode ray tube
34
and the loudspeaker
35
.
In other words, when a video signal reproduced from the recording medium by the separate video tape recorder is input via the external input terminal
32
, the reproduced video signal is supplied via the AGC circuit
23
to the television signal processing circuit
33
whether the video tape recorder
21
is in the recording mode or not.
The AGC circuit
23
generally detects the level of the horizontal synchronizing signal and adjusts the detected horizontal synchronizing signal so as to have a constant level, thereby adjusting the input signal to a constant level at which the signal can be recorded (this level is set to be 1 V
p-p
).
Incidentally, as video tape recorders have become widely used, the problem of unauthorized duplication of a video tape has been given a great deal of attention. Recently, therefore, a video tape which has been subjected to a so-called copy protection processing has been made available in order to protect against such unauthorized duplication.
In the copy protection processing, a pulse-like signal is superposed in the horizontal synchronizing signal portion of a video signal recorded on a video tape, so that the horizontal synchronizing signal is forcedly changed in level. When a video signal on which such a processing has been conducted is processed by the AGC circuit
23
, the resulting signal does not meet standards. When such an out-of-standard video signal is reproduced, the reproduced image is very unclear (or it is substantially filled with noise).
In the above-described television receiver with a video tape recorder, when a copy-protected reproduced video signal is supplied from the separate video tape recorder connected to the external input terminal
32
, the reproduced video signal must be passed through the AGC circuit
23
of the video tape recorder
21
. Even in the case where the reproduced video signal is merely displayed on the television receiver, therefore, there arises a problem in that the television receiver displays only a very unclear image.
In other words, when a copy-protected video signal which is reproduced by the separate video tape recorder is displayed on the above-described conventional television receiver, the resulting image is very unclear, thereby producing a problem in that it is impossible to view the image. This problem is produced also in the case where a copy-protected television signal is transmitted by radio waves and then received via the RF input terminal
28
.
SUMMARY OF THE INVENTION
The invention has been made in order to solve the above problem. It is an object of the invention to provide an external input signal processing circuit for a television receiver with a video tape recorder in which, even when a copy-protected video signal is externally input, a mere viewing can be done on the television receiver.
In order to attain the above object, the invention provides an external input signal processing circuit for a television receiver with a video tape recorder integrally incorporated therein, the video tape recorder having recording and reproducing functions, the external input signal processing circuit including: an automatic gain control circuit connected to an external input terminal of the video tape recorder; a video signal recording circuit connected to the automatic gain control circuit; a video signal reproducing circuit for reproducing a signal recorded on a recording medium; a changeover switch whose one input terminal is connected to an input (terminal) side of the automatic gain control circuit, the other input terminal is connected to the video signal reproducing circuit, and common terminal is connected to a television signal processing circuit for display; and a switch circuit for controlling the changeover switch so that the one input terminal and the common terminal of the changeover switch are connected to each other when the video tape recorder is in a recording mode.
Further, the invention provides an external input signal processing circuit for a television receiver with a video tape recorder integrally incorporated therein, the video tape recorder having recording and reproducing functions, the external input signal processing circuit including: an automatic gain control circuit connected to an external input terminal of the video tape recorder; a video signal recording circ
Bacon & Thomas
Funai Electric Co. Ltd.
Vincent David R.
LandOfFree
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