WILLIAM J MURPHY
Broker in Burlington, MA
License number
Massachusetts 62025
Issued Date
Dec 1, 1968
Expiration Date
May 16, 1980
Type
Broker
Address
Address
Burlington, MA 01803
Personal information
See more information about WILLIAM J MURPHY at radaris.comName
Address
Phone
4 Farnham Rd, Stoughton, MA 02072
49 Thornton St, Wollaston, MA 02170
49 Willow Dell, North Adams, MA 01247
4 Carrington Way, Haverhill, MA 01835
4 Chapaquoit Way, East Sandwich, MA 02537
Professional information
Swept Frequency Trap Jammer For Secure Television System
US Patent:
3989887, Nov 2, 1976
Filed:
Aug 28, 1975
Appl. No.:
5/608429
Inventors:
William D. Murphy - Burlington MA
Assignee:
GTE Laboratories Incorporated - Waltham MA
International Classification:
H04N 144
US Classification:
178 51
Abstract:
A jamming circuit for making unusable the television signal of a preselected channel includes a bridged T-trap filter having a pair of high Q circuits adapted to be tuned to the carrier frequency of the preselected channel, and a device for cyclically sweeping each tunable circuit through the video carrier frequency for the preselected channel. Each circuit is varied approximately. +-. 500 KHz from the carrier frequency, the cyclic sweeping rate being 14 KHz for one tunable circuit and 16 KHz for the other. Cyclic tuning is achieved by using varactors as part of the tuning capacity for each circuit, the varactors receiving a sawtooth waveform produced by two free-running oscillators. As a result of the jamming circuit, the television signal is modulated at a 14 KHz, 16 KHz and 2 KHz rate, thereby producing severe amplitude and phase distortion.
Scrambler And Decoder For Secure Television System
US Patent:
3996418, Dec 7, 1976
Filed:
Sep 2, 1975
Appl. No.:
5/609878
Inventors:
William D. Murphy - Burlington MA
Gerald Aaronson - Brookline MA
Gerald Aaronson - Brookline MA
Assignee:
GTE Laboratories Incorporated - Waltham MA
International Classification:
H04N 144
US Classification:
178 51
Abstract:
A scrambler for a television system alternately inverts the phase of the carrier which is modulated by the television signal. A binary coding signal controls the manner of the carrier-phase inversion. Phase inversion is obtained by combining the modulated normal carrier with an out of phase carrier having a maximum peak amplitude greater than the peak amplitude of the modulated carrier. The coding signal also frequency modulates the carrier for the scrambled television signal thereby providing a key for decoding at the television receiver. The decoder at the receiver reproduces the coding signal from the scrambled signal, removes the frequency modulation and combines the scrambled signal with a reproduced normal carrier at the time intervals corresponding to the presence of the phase-inverted carrier. An automatic gain control circuit insures that the decoded television signal has constant sync pulse amplitude for normal carrier intervals and inverted phase carrier intervals by controlling the reproduced normal carrier amplitude as a function of sync pulses in the normal carrier portion of the scrambled television signal.
Scrambler And Decoder For A Television Signal
US Patent:
3936593, Feb 3, 1976
Filed:
Aug 5, 1974
Appl. No.:
5/494653
Inventors:
Gerald Aaronson - Brookline MA
William D. Murphy - Burlington MA
William D. Murphy - Burlington MA
Assignee:
GTE Laboratories Incorporated - Waltham MA
International Classification:
H04N 144
US Classification:
178 51
Abstract:
An improved scrambler and decoder for a television signal is described wherein a television carrier is inverted in phase and subjected to low frequency amplitude modulation to obtain enhanced channel security. The carrier amplitude modulation is obtained with a coding signal which is transmitted as a pilot signal in the form of frequency modulation of the carrier. The coding signal is recovered at the decoder with a phase lock network and used to regenerate an unscrambled carrier. The coding signal provides information for special functions such as subscriber access control, program selection and the like.