Telephonic communications – Having light wave or ultrasonic link for speech or paging... – Including fiber optic link within telephone network
Patent
1987-09-02
1990-06-05
George, Keith E.
Telephonic communications
Having light wave or ultrasonic link for speech or paging...
Including fiber optic link within telephone network
379 98, 358 85, 358134, H04M 1100, H04N 714
Patent
active
049320475
ABSTRACT:
An improved video phone transmits a source image over a standard telephone line in conjunction with voice signals. The unique initialization protocol provides a hardware preamble for synchronizing a receiver clock, a software preamble for identifying the video image and disabling the audio, automatic gain control adjustment data and amplitude calibration data. The audio portion is disabled by coupling a capacitor across the telephone to effectively short the telephone. The telephone is placed across a bridge circuit which is provided with switches to balance the bridge in both the telephone and video modes. The transmitted and received signals pass through the same delay equalization circuit, so that half the equalization is done before transmission, with the remaining half being done after reception. Input and output selectors allow the same circuit to be used. The digital signals are level shifted up prior to being converted into analog, and then are shifted down again to reduce the effects of DC offset. The digital and analog voltage supplies are coupled together with a resistor and diode, and a capacitor is coupled between the analog supply and ground to combine the reset and voltage supply functions. An RC circuit providing 180.degree. of phase shift is coupled to the crystal oscillator to produce a clock which is locked into the series resoonant frequency of the oscillator. The camera and the rest of the circuitry are turned on and off by a switch coupled to panel which can be slid in front of the camera.
REFERENCES:
patent: 3612901 (1971-10-01), Loe
patent: 3725822 (1973-04-01), Eaton, Jr.
patent: 4394649 (1983-07-01), Suchoff et al.
patent: 4455663 (1984-06-01), Ragsdale
patent: 4485400 (1984-11-01), Lemelson et al.
patent: 4715059 (1987-12-01), Cooper-Hart et al.
patent: 4739394 (1988-04-01), Oda et al.
The Sharper Image, "Introducing Luma: The Telephone That Lets You See Who's Talking", Catalog, pp. 1-3, Aug. 1986, Received 7/17/86.
Brisko, Jr. William E.
Cooper-Hart Michael A.
Emmons Lawrence D.
Mackley James S.
Stefenel Rudolph S.
George Keith E.
Luma Telecom, Inc.
LandOfFree
Conversational video phone does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Conversational video phone, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Conversational video phone will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-497797