Television – Receiver circuitry
Reexamination Certificate
2000-11-07
2004-07-20
Hsia, Sherrie (Department: 2614)
Television
Receiver circuitry
C348S731000, C348S726000, C455S301000
Reexamination Certificate
active
06765626
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a digital television signal receiving unit (hereinafter merely called a receiving unit) that is preferable for receiving a digital type television signal transmitted by a ground wave.
2. Description of the Related Art
FIG. 4
illustrates a block arrangement of a related art receiving unit, wherein the receiving unit consists of a tuner section
31
, an OFDM demodulation circuit section
32
, a Fourier transform circuit section
33
, an error correction circuit section
34
, a control circuit section
35
, a connector
36
having a plurality of contact elements and a crystal oscillator
37
and the like are mounted on a printed circuit board
41
.
In this case, the tuner section
31
has a rectangular parallelpiped metallic case
31
a
and it is constructed such that a frequency conversion circuit and an A/D conversion circuit and the like (both of them are not shown) are mounted on a printed circuit board (not shown) housed in the metallic case
31
a
. Then, an input connector
31
b
receiving the television signal is fixed at the side surface under a state in which it is protruded in a longitudinal direction of the metallic case
31
a
and further the metallic case
31
a
has a plurality of terminals
31
c
protruded from the other side surface.
In this case, the OFDM demodulation circuit section
32
, the Fourier transform circuit section
33
, the error correction circuit
34
and the control circuit section
35
is formed into one integrated circuit chip and each of them is constructed as its individual package.
The printed circuit board
41
consists of by a rectangular multilayer substrate. The tuner section
31
is mounted on the printed circuit board
41
in such a way that the input connector
31
b
is protruded out of the end section
41
a
of the printed circuit board
41
. A plurality of terminals
31
c
protruded out of the side surface of the tuner section
31
are bent at a right angle and inserted into the printed circuit board
41
. In addition, the OFDM demodulation circuit section
32
and the Fourier transform circuit section
33
are arranged in sequence on the same lines arranged in the longitudinal direction of the tuner section
31
, the tuner section
31
and the OFDM demodulation circuit section
32
are mounted in such that they are near to each other and the OFDM demodulation circuit section
32
and the Fourier transform circuit section
33
are also mounted in such that they are near to each other.
The error correction circuit section
34
oppositely faces against the OFDM demodulation circuit section
32
, the control circuit section
35
faces oppositely against the Fourier transform circuit
33
and are mounted such that they are positioned in parallel near the arrangement of the OFDM demodulation circuit section
32
and the Fourier transform circuit section
33
. Then, a crystal oscillator
37
is mounted between the error correction circuit section
34
and the control circuit section
35
.
Further, the connector
36
, having a plurality of connecting elements, is mounted in opposition to the terminals
31
c
of the tuner section
31
.
Then, the terminals
31
c of the tuner section
31
and each of the terminals (not shown) of the OFDM demodulation circuit section
32
, the Fourier transform circuit section
33
, the error correction circuit section
34
and the control circuit
35
and the like is soldered to a predetermined conductive pattern (not shown) arranged on the printed circuit board
41
and connected to each other and connected to the contact elements (not shown) of the connector
36
. Then, various kinds of signals are generated by or received from the main body of the television receiver set through the connector
36
.
The tuner section
31
includes the frequency conversion circuit and the A/D conversion circuit, wherein a television signal of a tuned channel is converted into an intermediate frequency signal by the frequency conversion circuit, and the A/D conversion circuit may output a digital signal generated by sampling the intermediate frequency signal to the OFDM demodulation circuit section
32
.
In this arrangement, the printed circuit board
41
is provided with a conductive pattern (not shown), the terminals
31
c
of the tuner section
31
are connected to the OFDM demodulation circuit section
32
through this conductive pattern, the OFDM circuit section
32
and the Fourier transform circuit section
33
are connected to each other, and the OFDM demodulation circuit section
32
and the error correction circuit section
34
are connected to each other to transmit the aforesaid signal in sequence.
The control circuit section
35
is a microcomputer, wherein it controls operations of the OFDM demodulation circuit section
32
, the Fourier transform circuit section
33
and the error correction circuit section
34
in response to a control signal (that includes a tuning signal) sent from the main body of the television receiver (not shown) and further controls a tuning operation of the tuner section
31
.
Due to this fact, the control circuit section
35
and the terminals
31
c
; the control circuit section
35
and the OFDM demodulation circuit
32
; the control circuit section
35
and the error correction circuit section
34
; and the control circuit section
35
and the Fourier transform circuit section
33
are connected to each other to generate or receive the aforesaid control signal.
Further, the crystal oscillator
37
is used for generating a synchronous signal in case where the control circuit section
35
controls the operations of the OFDM demodulation circuit section
32
and the error correction circuit section
34
.
In the aforesaid receiving unit, since the tuner section
31
and the crystal oscillator
37
were fixed on the printed circuit board
41
, its assembling work became a troublesome work and at the same time its cost was increased under application of either the printed circuit board
41
or the connector
36
.
In addition, since the OFDM demodulation circuit section
32
to the error correction circuit section
34
were not shielded and mounted on the printed circuit board
41
, noises such as synchronizing signals (a vertical synchronizing signal and a horizontal synchronizing signal and the like) outputted from the main body part of the television receiver were induced at each of these circuit sections to be overlapped on the MPEG bit stream signal. This caused the image quality or the like to deteriorate. In cases where a level of the synchronizing signal is further high, this state produces some problems that badly influences the operations of the OFDM demodulation circuit section
32
or the error correction circuit section
34
and a reproduction of the accurate image becomes impossible.
SUMMARY OF THE INVENTION
In view of the foregoing, the present invention decreases costs by simplifying receiver structure and minimizing units influence to noise generated by the main body of the television receiver.
A digital television signal receiving unit embodiment of the present invention comprises a metallic case, a frequency conversion circuit for converting a frequency of a received digital television signal into an intermediate frequency signal or a base band signal and an OFDM signal processing circuit for processing either the intermediate frequency signal or the base signal and outputting an MPEG bit stream signal, housed in the metallic case. Operations of the frequency conversion circuit and the signal processing circuit are controlled by a control signal outputted from a control circuit arranged outside the metallic case.
In addition, a digital television signal receiving unit embodiment according to the present invention includes an OFDM signal processing circuit comprised of an A/D conversion circuit for converting either the intermediate frequency signal or the base band signal into a digital signal and an OFMD demodulation circuit for OFDM demodulating the digital signal and outputting a demodulati
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Hsia Sherrie
LandOfFree
Digital television signal receiving unit with simplified... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Digital television signal receiving unit with simplified..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Digital television signal receiving unit with simplified... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3246686