Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
1997-02-28
2002-11-19
Gandhi, Jayprakash N. (Department: 2841)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S816000, C174S034000
Reexamination Certificate
active
06483716
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a video cassette recorder (VCR) board. More particularly, it relates to a VCR having a preamplifier incorporated with its main circuit board. This application is based on Korean Patent Application No. 96-10610 which is incorporated by reference herein for all purposes.
FIG. 1
is a block diagram showing a general VCR. Referring to
FIG. 1
, when a deck portion
1
picks up a video signal recorded on a video tape (not shown) and outputs the picked up video signal, a preamplifier portion
2
amplifies the weak picked up video signal and outputs it to a video signal processing portion
3
. The video signal processing portion
3
processes the video signal reproduced from the tape, and then divides it into an image signal and an audio signal, and outputs the two signals.
Additionally, when recording a TV broadcast signal, a tuner
4
selects a TV broadcast signal and the video processing portion
3
performs a signal processing of the selected TV broadcast signal. Then the preamplifier portion
2
amplifies the signal processed by processing portion
3
, and the deck portion
1
records the TV broadcast signal on a video tape (not shown).
A conventional VCR has a preamplifier board which is separate from its main circuit board, as will be further described below.
FIG. 2
is a perspective view showing a portion of a conventional VCR whose preamplifier board
25
is separate from its main board
26
.
In
FIG. 2
, the video signal which is picked up from the video tape through a drum
22
in a deck
21
is output to a preamplifier board
25
through a connector cable
23
. The preamplifier circuitry (not shown) is located on the preamplifier board
25
and is sealed-up in a shielding case
24
in order to prevent the weak picked up video signal from being interfered with by external noise. The video signal which is picked up by the drum
22
is output from the drum
22
to the preamplifier board
25
through the connector cable
23
and is amplified by about 60 dB. The video signal amplified in the preamplifier board
25
is output to the video signal processing portion
3
of a main circuit board
26
.
The conventional preamplifier board
25
is vertically connected to the main board
26
as shown in FIG.
2
. That is to say, the preamplifier board
25
is conventionally mounted on the main board
26
at a right angle, which would make the preamplifier board
25
lie in a vertical plane, assuming that the main board
26
lies in a horizontal plane. Because of this vertical mounting of the preamplifier board
25
with respect to the main board
26
, the productivity of connecting the connector cable
23
between the drum
22
and the preamplifier board
25
is lowered since the inner space of a VCR set is narrowed by the preamplifier board
25
. Also, since the preamplifier board
25
is vertically connected to the main board
26
, it is hard to maintain a good grounding between the deck
21
and the shielding case
24
, because it is difficult to obtain a wide enough contact area between the deck
21
and the shielding case
24
. The result is that it is hard to obtain grounding for the shielding case
24
sufficient to remove the interference of external noise.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a VCR to improve the productivity of a VCR by incorporating a preamplifier board into the main circuit board and to remove the interference of noise by securing a wider grounding surface for a preamplifier shielding case.
To achieve the above object, there is provided a video cassette recorder (VCR) having a preamplifier incorporated with its main board. The VCR comprises a deck for picking up a video signal, a connector cable for supplying the video signal picked up by the deck to the preamplifier, a main board on which the preamplifier is incorporated, and a shielding case, contacting a portion of the deck, for shielding the preamplifier.
The shield case contacts a wider surface of the deck since it is level with the deck.
REFERENCES:
patent: 4578718 (1986-03-01), Parker et al.
patent: 4972190 (1990-11-01), Primeau et al.
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