Distribution of local video signal with consumer cable television signal

• US 5,585,837 A
• Filed: 03/15/1995
• Issued: 12/17/1996
• Est. Priority Date: 03/15/1995
• Status: Expired due to Fees

• Current Assignee: Dale Bruce Nixon
• Original Assignee: Dale Bruce Nixon
• Inventors: Nixon, Dale B.
• Primary Examiner(s): Kostak, Victor R.
• Assistant Examiner(s): Flynn, Nathan J.
• Application Number:
  US08/405,277
• Time in Patent Office: 643 Days
• Field of Search: 348/6, 348/8, 348/9, 348/554, 348/722, 348/724, 388/335
• US Class Current: 725/78
• CPC Class Codes: H04N 7/102 Circuits therefor, e.g. noise reducers, equalisers, amplifiers H04N7/108 takes precedence
• CPC Class Codes: H04N 7/104 Switchers or splitters
• CPC Class Codes: H04N 7/106 for domestic distribution
• CPC Class Codes: H04N 7/181 for receiving images from a plurality of remote sources

Abstract

A video signal processing and distribution apparatus receives a cable television signal which includes a plurality of television channels. The cable television signal is transferred through one or more band block filters, each of which can block a particular channel from the cable television signal. An oscillator is provided for each local video signal that is desired to be added into the cable television signal. Each oscillator produces a carrier signal within the band of a removed television channel. The local video signal modulates the carrier signal to produce a new channel signal that is combined with the cable signal, which has had at least one selected channel removed. The resulting modified cable signal is distributed to one or more television sets wherein each set can view a plurality of new locally generated channels which have been added to the cable television signal in place of previously existing channels.

Claims

1. An electronic apparatus for receiving a cable television signal and producing a modified cable signal, comprising:

a first input terminal for receiving said cable television signal,

a variable band block filter connected to said input terminal, said band block filter having a center frequency and an output terminal,

a second input terminal for receiving a video signal,

a variable frequency oscillator which produces an output signal having a frequency within the band of said band block filter, said oscillator having an output terminal,

a control switch connected to said band block filter and to said oscillator,

a modulator having input terminals thereof connected to said oscillator output terminal and to said second input terminal, said modulator having an output terminal, and

an output terminal of said apparatus, said apparatus output terminal coupled to said band block filter output terminal and to said modulator output terminal, and

wherein said modified cable signal is provided at said apparatus output terminal.

2. An electronic apparatus as recited in claim 1 including a signal combiner having input terminals thereof connected to the output terminals of said band block filter and said modulator and said combiner having an output terminal thereof connected to said apparatus output terminal.

3. An electronic apparatus as recited in claim 1 including a driver circuit connected to the output terminals of said band block filter and said modulator output terminal and having a plurality of outputs each comprising said apparatus output terminal.

4. An electronic apparatus as recited in claim 1 wherein said control switch is a rotating thumbwheel switch.

5. An electronic apparatus as recited in claim 1 wherein said variable band block filter comprises a plurality of selectable fixed band block filters.

6. An electronic apparatus for receiving a cable television signal and producing a modified cable signal, comprising:

a first input terminal for receiving said cable television signal,

a plurality of variable band block filters connected in series and coupled between said first input terminal and a filter output terminal,

a plurality of video signal input terminals,

a plurality of variable frequency oscillators,

a plurality of modulators, each said modulator connected to a respective one of said oscillators into a respective one of said video signal input terminals, and each set modulator having an output terminal,

a plurality of control switches, each control switch connected to a respective one of said variable band block filters and to a respective one of said variable frequency oscillators,

a signal combiner having a plurality of inputs which are respectively connected to said modulator output terminals and to said filter output terminal, said signal combiner having an output terminal, said signal combiner having an output terminal, and

an output terminal for said apparatus, said signal combiner output terminal coupled to said apparatus output terminal and wherein said modified cable signal is provided at said apparatus output terminal.

7. An electronic apparatus as recited in claim 6 including a driver circuit having an input coupled to said filter output terminal and to said modulator output terminals and having a plurality of outputs each comprising said apparatus output terminal.

8. An electronic apparatus as recited in claim 6 wherein each said variable band block filter comprises a plurality of selectable fixed band block filters.

9. A television system comprising:

a video camera which produces a baseband video signal,

a television set,

an electronic apparatus, comprising;

a first input terminal for receiving a cable television signal which includes a plurality of television channels,

a variable band block filter connected to said input terminal, said band block filter having a band width approximately equal to the bandwidth of each of said television channels and having a selectable center frequency approximately equal to the center frequency for any one of said television channels, and said band block filter having an output terminal,

a second input terminal for receiving said video signal,

a variable frequency oscillator having an output terminal,

a modulator having input terminals thereof connected to said second input terminal and to said oscillator output terminal, said modulator having an output terminal,

an output terminal offset apparatus, said apparatus output terminal coupled to said band block filter output terminal and to said modulator output terminal,

an input switch connected to said variable band block filter for selecting a center frequency thereof and connected to said oscillator for selecting the frequency thereof, and

said television set coupled to said output terminal of said apparatus wherein said cable television channels, except for said one television channel, and said video camera video signal can be viewed at said television set.

10. A television system as recited in claim 9 including a signal combiner having input terminals thereof connected to the output terminals of said band block filter and said modulator and having an output terminal thereof connected to said apparatus output terminal.

11. A television system as recited in claim 9 wherein said electronic apparatus has a plurality of said output terminals.

12. A method for producing a modified cable signal from a received cable television signal which includes a plurality of channels, comprising the steps of:

generating a channel selection signal,

operating a variable band block filter, which is connected to receive said cable television signal, in response to said channel selection signal to have a blocked band having a center frequency and bandwidth to block a selected one of the channels of said received cable television signal to thereby produce a blocked channel signal,

generating, in response to said channel selection signal, a carrier signal having a frequency which is within the band of said blocked band,

modulating said carrier signal with a baseband video signal to produce a new channel signal, and

combining said blocked channel signal with said new channel signal to produce said modified cable signal.

13. A method for producing a modified cable signal as recited in claim 12 wherein said step of operating a variable band block filter includes selecting one of a plurality of fixed band block filters.