Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
1997-06-06
2001-05-01
Kelley, Chris (Department: 2615)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C386S349000, C360S015000, C369S084000
Reexamination Certificate
active
06226442
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to audio and video recording, and more particularly, to a high speed copying system for a double-deck complex video apparatus.
2. Description of the Prior Art
Generally, a double-deck video cassette recorder has at least two video cassette decks capable of tape-to-tape copying of video data therebetween, where one deck is set to a playback mode, and the other deck is set to a record mode.
As shown in
FIG. 1
, a conventional double-deck complex video apparatus includes an amplifier
1
for amplifying a signal picked up through a playback head PB, a demodulator
2
for demodulating the amplified signal of the amplifier
1
into an original signal, a modulator
3
for modulating the signal demodulated in the demodulator
2
, and an automatic gain control (AGC) circuit
4
for controlling gain of the signal modulated in the modulator
3
.
First, to copy high fidelity (Hi-Fi) tape using the above double-deck apparatus, if the tape is set within the playback deck, the FM audio signal picked up by the playback head PB is amplified through the amplifier
1
, and then, the amplified signal is demodulated by the demodulator
2
as the original signal. The original signal is then input to the modulator
3
, and is modulated as a proper signal for recording. Thereafter, the signal gain of the modulated signal is controlled by AGC circuit
4
, and is recorded on the tape.
To copy data recorded on the first recording media received in the first deck to the second recording media received in the second deck, for the case in which relevant data is selected, the FM audio signal picked up by the playback head PB is amplified through the amplifier
1
at a predetermined level, and then, the amplified signal is demodulated by the demodulator
2
as the original signal. The original signal is modulated by the modulator
3
as the modulated signal which is applied through AGC circuit
4
to the recording head REC to be recorded on the recording media.
In a conventional copying procedure, since data copying must be performed through the demodulating and modulating procedures, if data is copied at N times a reference speed, the carrier frequency increases by a factor of N so that the degradation occurs in the modulator and the demodulator.
Another conventional FM audio signal copying method in the prior art employs head switching. Typically, the head switching type of copying method exhibits undesirable switching noises.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a high speed copying system for a double-deck complex video apparatus which avoids modulator/demodulator-related degradation effects, and which exhibits low or minimal switching noises.
In an exemplary embodiment of the present invention, a high speed copying system for use in a double-deck video apparatus includes a system controller responsive to input copy speed data for generating control signals that generally control operation of the system. First and second switches are responsive to at least one of the control signals supplied from the system controller for supplying power to first and second recording heads. First and second filters are used to filter an output signal picked up by a pick-up means in response to one of the control signals relating to a copy mode from the system controller. Each filter has a passband that includes a frequency Nf
c
, where N is a number related to copy speed and f
c
is a reference carrier frequency. Automatic gain control circuits may be used to automatically control gain of the signals output from the respective filters for application to the recording heads.
Optionally, the first and second filters may be band pass filters with a variable passband according to the copy speed.
The copying system may include a third filter for filtering an output signal picked up from a playback head, where the third filter has a passband that includes the reference carrier frequency f
c
.
REFERENCES:
patent: 5083225 (1992-01-01), Morisaki et al.
patent: 5493414 (1996-02-01), Inoue et al.
patent: 5715104 (1998-02-01), Takada et al.
Dilworth & Barrese LLP
Kelley Chris
Onuaku Christopher
Samsung Electronics Co,. Ltd.
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