Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
1998-04-16
2002-02-12
Nguyen, Huy (Department: 2615)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C386S349000
Reexamination Certificate
active
06347179
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a video signal processor having an oscillation circuit for generating a reference signal or the like using a crystal unit.
2. Description of the Related Art
A video cassette recorder uses a microcomputer for controlling the operation of the main unit and the rotation speed of a capstan motor and the like. The microcomputer is adapted to also keep the time of day at the power outage time when the commercial power supply is stopped.
FIG. 1
shows the related art for performing the above operation, wherein a microcomputer
291
is provided with two oscillation circuits
295
and
296
. A 32.768-kHz crystal unit
292
is connected to the oscillation circuit
295
and a 12-MHz crystal unit
293
is connected to the oscillation circuit
296
.
In the operation standby state, only the oscillation circuit
295
is operated and an output thereof is led to a central processing unit (CPU)
297
. Thus, the microcomputer
291
performs the time-keeping operation with less power consumption, and also performs the control operation required in the standby state.
On the other hand, when the operation state is entered, an output of the oscillation circuit
296
is led to the CPU
297
. Thus, the microcomputer
291
performs the high-speed operation in accordance with a high-frequency clock signal for controlling the rotation speed of the capstan motor and the like, or other operations.
As described above, the crystal unit
292
for generating a clock signal in the standby state and the crystal unit
293
for generating a clock signal in the operation state are connected to the microcomputer
291
. That is, the microcomputer
291
requires two crystal units
292
and
293
. However, since the crystal units
292
and
293
are expensive devices, use of the two crystal units
292
and
293
results in a rise in cost of the video cassette recorder.
To enhance accuracy and stability of the receiving frequencies, a video signal receiver such as a video cassette recorder, a television set, and the like, uses a phase locked loop (PLL) circuit to generate a local oscillation signal of a predetermined frequency for determining the receiving frequency. In such a configuration, a reference signal for making a phase comparison with an output of a local oscillation circuit is indispensable. Thus, in a conventional receiver, the PLL circuit is provided with an exclusive crystal unit for generating the reference signal.
However, the crystal unit is an expensive device as described above and in case of using a PLL circuit for determining the receiving frequency, the number of crystal units to be used is increased, resulting in a rise in cost of the system.
FIG. 2
is a block diagram showing the configuration of a conventional video cassette recorder with a television set. That is, a tuner unit
391
takes out a video signal from a received signal and sends the taken-out video signal to a recording/reproducing unit
396
. At the operation time except reproduction, a video signal processing unit
393
generates primary-color chrominance signals of R, G, and B from the video signal received through the recording/reproducing unit
396
from the tuner unit
391
. A cathode-ray tube (CRT) unit
394
amplifies the primary-color chrominance signals generated by video signal processing unit
393
to a predetermined level and drives a CRT by the amplified primary-color chrominance signals. At the recording time, the recording/reproducing unit
396
applies predetermined processing to the video signal for generating a signal to be recorded, and feeds the generated signal into a rotary head
397
. At the reproducing time, the recording/reproducing unit
396
applies predetermined processing to a reproduced signal output from the rotary head
397
for reproducing the video signal, and outputs the reproduced video signal to the video signal processing unit
393
. As a result, an image is displayed on the CRT unit
394
by the reproduced video signal.
In the operation described above, the video signal processing unit
393
requires a signal (reference subcarrier) phase-synchronized with a burst signal in the video signal. Thus, the video signal processing unit
393
uses a crystal unit
395
to generate a reference subcarrier. The recording/reproducing unit
396
requires a reference subcarrier at the recording time and a reference signal used as reference of a burst signal at the reproducing time. Thus, the recording/reproducing unit
396
uses a crystal unit
398
to generate a reference subcarrier at the recording time and a reference signal at the reproducing time. The crystal units
395
and
398
are connected to the video signal processing unit
393
and the recording/reproducing unit
396
respectively. However, since the crystal units are expensive devices as described above, use of two crystal units results in a rise in the total cost of the parts to be used, raising a large bottleneck for reducing the manufacturing cost.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a video signal processor which can reduce the number of crystal units to be used.
In order to attain the above object, the invention provides a video signal processor including: a reference signal generating circuit provided with at least an oscillation circuit for generating a reference signal corresponding to a burst signal; a Y/C separation circuit for separating a video signal into a luminance signal and a chrominance signal with output of the reference signal generating circuit as a clock signal; and a microcomputer for controlling an operation of the video signal processor with the output of the reference signal generating circuit as a clock signal.
Further, the invention provides a video signal recording medium reproducer including: a reproducing unit for reproducing a video signal recording medium; a chrominance signal restoration circuit for restoring a chrominance signal based on a signal reproduced from the video signal recording medium by the reproducing unit; a reference signal generating circuit for supplying a reference signal corresponding to a carrier of the chrominance signal to the chrominance signal restoration circuit; and a microcomputer for controlling an operation of the video signal recording medium reproducer with the reference signal from the reference signal generating circuit as a clock signal.
Furthermore, the invention provides a video signal receiver including: a mixer circuit for making frequency conversion of an RF signal from an RF amplifier circuit to an IF signal based on a local oscillation signal from a local oscillation circuit; a PLL circuit for setting an output frequency of the local oscillation circuit to a frequency corresponding to a receiving frequency by making a phase comparison between the local oscillation signal and a first reference signal; and chrominance signal circuit for generating a chrominance signal by using a second reference signal based on the IF signal from the mixer circuit, wherein the second reference signal is also supplied to the PLL circuit as the first reference signal.
Still further, the invention provides a video cassette recorder with a television set including: a recording/reproducing unit for generating a recording signal based on a video signal fed from a tuner unit and outputting the generated recording signal to a rotary head at a recording time and for generating a video signal based on a reproduced signal output from the rotary head and outputting the generated video signal at a reproducing time; and a video signal processing unit for generating a primary color chrominance signal from the same video signal as the video signal fed into the recording/reproducing unit at the recording time and for generating a primary color chrominance signal from the video signal generated by the recording/reproducing unit at the reproducing time, wherein the recording/reproducing unit includes an oscillation circuit for executing oscillation phase-synchronized with a burst signal
Bacon & Thomas
Funai Electric Co. Ltd.
Nguyen Huy
LandOfFree
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