System for selectively interconnecting audio-video sources and receivers

• US 5,389,963 A
• Filed: 02/05/1992
• Issued: 02/14/1995
• Est. Priority Date: 02/05/1992
• Status: Expired due to Term

• Current Assignee: Library Video Company
• Original Assignee: Dynacom Corporation
• Inventors: Lepley, John A., Lepley, John A. Jr.
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): URBAN, EDWARD F
• Application Number:
  US07/831,352
• Time in Patent Office: 1,105 Days
• Field of Search: 358/86, 455/3.1, 455/4.1, 455/4.2, 455/5.1, 455/6.1, 380/5, 380/10, 348/6, 348/7, 348/8, 348/12, 359/125, 359/137, 359/142, 359/146
• US Class Current: 725/144
• CPC Class Codes: H04N 7/17318 Direct or substantially direct transmission and handling of requests
• CPC Class Codes: H04N 7/17336 Handling of requests in head-ends
• CPC Class Codes: H04N 7/181 for receiving images from a plurality of remote sources

Abstract

A system for selectively interconnecting a plurality of audio/video sources and a plurality of audio/video communication devices including a single switch, a mixer to combine the audio and video signals as a single signal from a source to the switch and a modulator for modulating the video signal after the switch for optical transmission to the communication devices. The modulated audio and video signals directly drive an optical transmitter as a composite signal. A programmable interface is provided at the sources and at the communication devices for translating system remote control signals to source and communication device control signals for the connected device. The interface provides ALL CALL overrides.

Claims

1. A system for interconnecting a plurality of sources of audio and video signals and a plurality of audio and video communication devices comprising:

switch means for selectively connecting said plurality of audio and video signals from said plurality of sources at its inputs to its outputs;

a plurality of first modulating means for receiving and modulating an audio signal from a respective source and providing said modulated audio signal as said audio signal input to said switch means;

a plurality of transmitter means, connected to a respective output of said switch means and including second modulating means for modulating received video signals, for transmitting said modulated video signals and received modulated audio signals simultaneously at an output; and

a plurality of receiver means connected to said output of a respective transmitter means for receiving, separating and demodulating said transmitted video and audio signals and providing said demodulated video and audio signals at an output for a respective communication device.

2. A system according to claim 1 including:

a plurality of mixing means for receiving and combining said modulated audio signal from a respective first modulating means and a video signal from a respective source and providing said combined signal as said audio and video signal input to said switch means; and

a plurality of separating means for separating a combined signal of a respective output of said switch means into said video signal to be modulated by a respective second modulating means and said modulated audio signal.

3. A system according to claim 2 wherein said mixing means includes a differential amplifier receiving said modulated audio signal on one of its inputs and said video signal on its other input.

4. A system according to claim 1

wherein said audio signals are stereo;

including a plurality of third modulating means for receiving and modulating said stereo audio signals with said first modulating means from a respective source and providing said modulated audio signals as said audio inputs to said switch means; and

wherein said receiver means demodulates said stereo audio signals and provides said demodulated stereo audio signals at its output.

5. A system according to claim 1 wherein said first and second modulating means frequency modulate said video and audio signals respectively in the RF range.

6. A system according to claim 1 wherein said transmitter means and receiver means are optical and are connected by optical transmission lines.

7. A system according to claim 1 wherein said transmitter means and said receiver means each include a power means for converting AC and DC power to DC power having values of V, V/2 and ground representing V+, ground and V-respectively.

8. A system according to claim 7 wherein said power means includes:

first and second power input terminals and a ground input terminal;

power bus and ground bus;

said ground input terminal being connected to said ground bus;

first pair of diodes connecting said first and second power input terminals to said power bus; and

second pair of removable diodes connecting said first and second power input terminals to said ground bus.

9. A system according to claim 1 wherein said first modulating means is a voltage controlled oscillator having a tuned circuit of a capacitor and an inductor for determining the frequency of modulation.

10. A system according to claim 9 wherein said receiver means each include a demodulator means for said audio signal having a tuned circuit of a capacitor and an inductor for determining the frequency of demodulation.

11. A system according to claim 9 wherein:

said first modulating means includes means for compressing and limiting said received audio signals before modulation; and

said receiver means includes means for expanding said demodulated audio signals.

12. A system according to claim 9 including a thermistor thermally and electrically connected to said first modulating means for temperature compensating the modulation of said first modulating means.

13. A system according to claim 1 wherein said switch means and receiver means are connected by coaxial electrical transmission lines.

14. A system according to claim 1 wherein:

said first modulating means and said second modulating means each include only a voltage controlled oscillator portion of a phase-locked loop; and

said receiver means each include first demodulator means and said second demodulator means each include a phase-locked loop for demodulating said separated audio and video signals.

15. A system according to claim 1:

wherein each of said sources includes audio/video port and remote control port;

wherein each of said communication devices includes audio/video port and remote control port for communicating audio/video signals received at its audio/video port and generating system remote control signals at its remote control port;

including a plurality of source interface means each having one or more source inputs connected to said audio/video port of one or more of said sources, having one or more source remote control outputs connected to said remote control port of one or more of said sources, having a system remote control input and having a source audio/video output; and

each of said source interface means being programmable to directly convert system remote control signals to source remote control signals for the source connected to said interface means on a one to one basis.

16. A system according to claim 15 wherein at least one of said remote control input ports of said sources is an optical receiver and at least one of said remote control outputs of said source interface means is an optical transmitter.

17. A system according to claim 15 wherein said source interface means each include multiplexed means for selecting which of the sources connected to it is interfaced to said switch means.

18. A system according to claim 17

including all call means connected as a source input for each of said source interface means for providing an all call audio/video signal common to all source interface means;

and

wherein said multiplexer means of each source interface means selects said all call signal as a source for an all call condition.

19. A system according to claim 15 wherein said said transmitter means and said receiver means each include means for communication of said systems remote control signals by dual tone multiple frequency modulation.

20. A system according to claim 15 wherein:

at least one of said communication devices includes a display screen and a computer control entry device;

one of said sources is a computer; and

said switch mean selectively connects said display screen and said computer control entry device and said computer.

21. A system according to claim 20 wherein said computer control entry device is wireless and said computer has a wireless entry device port connected to one of said source interface means.

22. A system according to claim 15 wherein said source interface means includes means for generating video signals from stored data in response to system remote control signals.

23. A system according to claim 15

wherein each of said communication devices communicating audio/video signals received at its audio/video port and responding to communication device remote control signals at its remote control port;

and

including a plurality of communication device interface means being programmable for directly converting system remote control signals to communication device remote control signals for the communication device connected to said communication device interface means on a one to one basis and transmitting system remote control signals.