United Technologies Corporation

Sensormatic Electronics Corporation

Thomas J Ray

Thomas J Rebeschi

Glenn C Waehner

Christopher M Mullins

John P McDonough

A video surveillance system includes a remotely controllable video camera which generates a video signal, a video switch, a cable for transmitting the video signal from the video camera to the video switch, a control circuit connected to the cable for generating control signals to be transmitted to the video camera via the cable, and a control signal receiver associated with the camera and connected to the cable for receiving the control signals transmitted via the cable. The control signal receiver includes a detection circuit for automatically detecting the length of the cable and generating an adjustment signal indicative of the detected length of the cable. The control signal receiver also includes an adjustable circuit element which is adjusted on the basis of the adjustment signal so as to compensate for the detected length of the cable. The automatic cable compensation in the control signal receiver provides reliable detection of the camera control signals. Automatic cable-length compensation of the video signal is also provided on the basis of the adjustment signal.

Automatic video cable compensation system

The phosphor screen of a cathode ray tube (CRT) has its phosphor coating protected against damage caused by a stationary or low sweep velocity electron beam that strikes its surface, by removal of the video signal that controls the beam whenever there is a simultaneous presence of video signal and absence of a proper horizontal or vertical sweep signal.

Cathode ray tube phosphor protection circuit

A cathode ray tube employing magnetic deflection coils for deflecting the electron beam in the horizontal and vertical directions, is corrected for the astigmatism error created by the non-uniform magnetic deflection field which causes a predictable elliptical distortion of the electron beam, through the use of two sets of correction coils mounted on a common annular magnetic core located on the neck of the CRT, which distorts the electron beam prior to its entry into the magnetic deflection field in a manner that is complementary to the distortion created by the non-uniform magnetic deflection field. The excitation currents for the correction coils are derived from the horizontal (Vx) and vertical (Vy) beam deflection voltage signals, in such a manner that the excitation current for the first correction coil is proportional to Vx.sup.2 - Vy.sup.2, and the excitation for the second correction coil is proportional to 2.sup.. Vx.sup.. Vy.

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Yonkers, NY, United States of America

Thomas J Ray