Signal distribution circuit

• US 6,751,803 B1
• Filed: 05/24/2000
• Issued: 06/15/2004
• Est. Priority Date: 05/24/1999
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Matsuura, Syuuji
• Primary Examiner(s): Miller, John
• Assistant Examiner(s): Shang, Annan Q.
• Application Number:
  US09/576,995
• Time in Patent Office: 1,483 Days
• Field of Search: 725/127, 725/128, 725/131, 725/133, 725/139, 725/140, 725/151, 725/152, 725/132, 725/100, 725/89, 725/60, 348/725, 348/726
• US Class Current: 725/127
• CPC Class Codes: H04N 7/102 Circuits therefor, e.g. noise reducers, equalisers, amplifiers H04N7/108 takes precedence

Abstract

Received digital CATV signals are branched by a directional coupler into signals flowing in a through direction and signals flowing in a branch direction. The signals output from the directional coupler in the through direction are then fed through an extraction circuit, a variable attenuator, and a wide-band amplifier so as to have a desired frequency range and a desired level, and are then fed to a distributor so as to be distributed, for output, into downstream signals to be fed to a downstream tuner and CATV signals to be fed to an analog/digital tuner. The signals output from the directional coupler in the branch direction are fed through a band-pass filter and a wide-band amplifier to a distributor so as to be distributed, for output, into VHF signals and FM signals. Upstream signals are fed through an extraction circuit to a terminal at which the CATV signals are received.

Claims

1. A signal distribution circuit for a CATV converter for distributing CATV signals into signals for an analog/digital tuner, signals for a downstream tuner, and other signals, comprising:

a directional coupler for distributing input CATV signals into signals that flow in a through direction and signals that flow in a branch direction;

an extraction circuit for permitting, out of the signals output from the directional coupler in the through direction, only the signals for an analog/digital tuner and the downstream signals to pass therethrough;

a gain control circuit for adjusting a gain of signals output from the extraction circuit;

a first output terminal for connection to an analog/digital tuner for receiving CATV signals;

a second output terminal for connection to a tuner for receiving downstream signals;

a distributor for distributing the signals of which the gain has been adjusted by the gain control circuit to the first and second output terminals; and

a circuit for processing the signals output from the directional coupler in the branch direction.

2. A signal distribution circuit for a CATV converter for distributing cable television broadcast signals transferred across a cable into signals for an analog/digital tuner, signals for a downstream tuner, VHF signals, and FM signals, comprising:

a directional coupler for distributing input CATV signals into signals that flow in a through direction and signals that flow in a branch direction;

a first extraction circuit for permitting, out of the signals output from the directional coupler in the through direction, only signals having predetermined frequencies to pass therethrough;

a variable attenuator for variably attenuating signals output from the first extraction circuit;

a wide-band amplifier for amplifying signals output from the variable attenuator;

a first output terminal for connection to an analog/digital tuner for receiving CATV signals;

a second output terminal for connection to a tuner for receiving downstream signals;

a first distributor for distributing signals output from the wide-band amplifier to the first and second output terminals;

a filter for permitting, out of the signals output from the directional coupler in the branch direction, only VHF signals and FM signals to pass therethrough;

an amplifier for amplifying signals output from the filter; and

a second distributor for distributing signals output from the amplifier into two groups of signals.

3. The signal distribution circuit as claimed in claim 2, further comprising:

an upstream signal input terminal; and

a second extraction circuit for extracting input upstream signals and feeding them to an output end of a through-direction path of the direction coupler,

wherein the directional coupler feeds the upstream signals to a CATV signal input terminal.

4. A signal distribution circuit for a CATV converter for distributing CATV signals into signals for an analog/digital tuner, signals for a downstream tuner, and other signals, comprising:

a first directional coupler for distributing input CATV signals into signals that flow in a through direction and signals that flow in a branch direction;

an extraction circuit for permitting, out of the signals output from the first directional coupler in the through direction, only the signals for an analog/digital tuner and the downstream signals to pass therethrough;

a first output terminal for connection to an analog/digital tuner for receiving CATV signals;

a second output terminal for connection to a tuner for receiving downstream signals; and

a second directional coupler for distributing signals output from the extraction circuit into signals that flow in a through direction and signals that flow in a branch direction, and feeding the signals flowing in the through direction to the first output terminal and the signals flowing in the branch direction to the second output terminal.

5. A signal distribution circuit for a CATV converter for distributing cable television broadcast signals transferred across a cable into signals for an analog/digital tuner, signals for a downstream tuner, VHF signals, and FM signals, comprising:

a first directional coupler for distributing input CATV signals into signals that flow in a through direction and signals that flow in a branch direction;

a first extraction circuit for permitting, out of the signals output from the directional coupler in the through direction, only signals having predetermined frequencies to pass therethrough;

a first output terminal for connection to an analog/digital tuner for receiving CATV signals;

a second output terminal for connection to a tuner for receiving downstream signals;

a second directional coupler for distributing signals output from the first extraction circuit into signals that flow in a through direction and signals that flow in a branch direction, and feeding the signals flowing in the through direction to the first output terminal and the signals flowing in the branch direction to the second output terminal;

a filter for permitting, out of the signals output from the first directional coupler in the branch direction, only VHF signals and FM signals to pass therethrough;

a third output terminal for connection to a VHF tuner;

a fourth output terminal for connection to an FM tuner; and

a distributor for distributing signals output from the filter to the third and fourth terminals.

6. The signal distribution circuit as claimed in claim 5, further comprising:

an upstream signal input terminal; and

a second extraction circuit for feeding input upstream signals to a through-direction path of the first directional coupler.

7. A signal distribution circuit for a CATV converter for distributing cable television broadcast signals transferred across a cable into signals for an analog/digital tuner, signals for a downstream tuner, VHF signals, and FM signals, comprising:

a first extraction circuit for permitting, out of input CATV signals, only signals having predetermined frequencies to pass therethrough;

a first directional coupler for distributing signals output from the first extraction circuit into signals that flow in a through direction and signals that flow in a branch direction;

a first output terminal for connection to an analog/digital tuner for receiving CATV signals;

a second output terminal for connection to a tuner for receiving downstream signals;

a second directional coupler for distributing the signals output from the first directional coupler in the through direction into signals that flow in a through direction and signals that flow in a branch direction, and feeding the signals flowing in the through direction to the first output terminal and the signals flowing in the branch direction to the second output terminal;

a second extraction circuit for permitting, out of the signals output from the first directional coupler in the branch direction, only VHF signals and FM signals to pass therethrough;

a third output terminal for connection to a VHF tuner;

a fourth output terminal for connection to an FM tuner; and

a distributor for distributing signals output from the second extraction circuit to the third and fourth terminals.

8. The signal distribution circuit as claimed in claim 7, further comprising:

an upstream signal input terminal; and

a third extraction circuit for extracting input upstream signals and feeding them to a CATV signal input terminal.

9. A signal distribution circuit for a CATV converter for distributing cable television broadcast signals transferred across a cable into signals for an analog/digital tuner, signals for a downstream tuner, VHF signals, and FM signals, comprising:

a CATV signal input terminal;

a first extraction circuit for permitting, out of signals received at the CATV signal input terminal, CATV signals to pass therethrough;

a gain adjustment circuit for adjusting a level of signals output from the first extraction circuit to a predetermined level;

a wide-band amplifier for amplifying signals output from the gain adjustment circuit;

a first output terminal for connection to an analog/digital tuner for receiving CATV signals;

a second output terminal for connection to a tuner for receiving downstream signals;

a first distributor for distributing signals output from the wide-band amplifier into two groups of signals and feeding one of those two groups of signals to the first output terminal;

a filter for permitting only VHF signals and FM signals to pass therethrough;

a second distributor for distributing the other of the two groups of signals output from the first distributor to the second output terminal and the filter;

a third output terminal;

a fourth output terminal; and

a third distributor for distributing signals output from the filter to the third and fourth output terminals.

10. The signal distribution circuit as claimed in claim 9, further comprising:

an upstream signal input terminal; and

a second extraction circuit for feeding upstream signals received at the upstream signal input terminal to the CATV signal input terminal.

11. A signal distribution circuit for a CATV converter for distributing cable television broadcast signals transferred across a cable into signals for an analog/digital tuner, signals for a downstream tuner, VHF signals, and FM signals, comprising:

a CATV signal input terminal;

a first extraction circuit for permitting, out of signals received at the CATV signal input terminal, CATV signals to pass therethrough;

a variable attenuation circuit for performing automatic gain control on signals output from the first extraction circuit;

a wide-band amplifier for amplifying signals output from the variable attenuation circuit;

a first output terminal for connection to an analog/digital tuner for receiving CATV signals;

a second output terminal for connection to a tuner for receiving downstream signals;

a first distributor for distributing signals output from the wide-band amplifier into two groups of signals and feeding one of those two groups of signals to the first output terminal;

a filter for permitting only VHF signals and FM signals to pass therethrough;

a directional coupler for distributing the other of the two groups of signals output from the first distributor to the second output terminal and the filter;

a third output terminal;

a fourth output terminal; and

a second distributor for distributing signals output from the filter to the third and fourth output terminals.

12. The signal distribution circuit as claimed in claim 11, further comprising:

an upstream signal input terminal; and

a second extraction circuit for feeding upstream signals received at the upstream signal input terminal to the CATV signal input terminal.

13. A signal distribution circuit for a CATV converter for distributing cable television broadcast signals transferred across a cable into signals for an analog/digital tuner, signals for a downstream tuner, VHF signals, and FM signals, comprising:

a CATV signal input terminal;

a first extraction circuit for permitting, out of signals received at the CATV signal input terminal, CATV signals to pass therethrough;

a first output terminal for connection to an analog/digital tuner for receiving CATV signals;

a second output terminal for connection to a tuner for receiving downstream signals;

a first distributor for distributing signals output from the first extraction circuit into two groups of signals;

a first circuit for adjusting a gain of one of the groups of signals output from the first distributor and feeding those signals to the second output terminal;

a second circuit for adjusting a gain of the other of the groups of signals output from the first distributor;

a filter for permitting only VHF signals and FM signals to pass therethrough;

a second distributor for distributing signals output from the second circuit into two groups of signals and feeding one of those two groups of signals to the first output terminal and the other to the filter;

a third output terminal;

a fourth output terminal; and

a third distributor for distributing signals output from the filter to the third and fourth output terminals.

14. The signal distribution circuit as claimed in claim 13, wherein the first and second circuits are each composed of a variable attenuator having an automatic gain control function and a wide-band amplifier.

15. The signal distribution circuit as claimed in claim 13, further comprising:

an upstream signal input terminal; and

a second extraction circuit for feeding upstream signals received at the upstream signal input terminal to the CATV signal input terminal.