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4499606 Reception enhancement in mobile FM broadcast receivers and the like
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New Patents noise voltage is predominantly obtained by amplifying the noise produced within the IFpassband of the IF-input stage.
4499606
not perceived by the user of the receiver. Sensitivity to switching is dependent on the rate of change of the received signal amplitude and on the modulation frequency of the received signal so that the system responds both to an overall reduction in received signal strength and to reduction in the strength of the high frequency portions of the received signal.
RECEPTION ENHANCEMENT IN MOBILE FM BROADCAST RECEIVERS AND THE LIKE William R Rambo assigned to SRI International p~oTaacao~
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4499609 SYMMETRICALLY CLAMPED FIBER OPTIC RECEIVER Willis M Muska assigned to International Telephone and Telegraph Corporation
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A system for enhancing the quality of a signal received by a mobile FM transmitter by reducing the adverse effects of multipath transmission to the receiver. A pair of antennas is provided, and each antenna is arranged to receive transmitted signals that traverses a different path. The signal produced in the receiver by one antenna is compared with a reference threshold and when the amplitude of the signal falls below the reference threshold, the receiver switches to the other antenna. The signal amplitude is sensed in a high frequency portion of the receiver, i.e. before detection or demodulation, so that switching between antennas occurs rapidly and is normally
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In a fiber optic receiver of the type comprising a photodetector, a preamplifier, a postamplifier and a voltage comparator for quantizing the output to a logic level signal, the improvement comprising symmetrical clamp means interposed between said postamplifier and said voltage comparator.
F o r information about P A T S E A R C H "
Pergamon InfoLine Inc. 1340 Old Chain Bridge Road McLean, Virginia 22101 USA Telephone (703) 442-0900 Telex: 90-1811
Pergamon InfoLine Limited 12 Vandy Street London EC2A 2DE England Telephone (01) 377-4650 Telex: 8814614
Pergamon Press Canada Ltd 150 Consumers Road, Suite 104 Willowdale, Ontario Canada M2J IP9 Telephone (416) 497-8337
New Patents noise voltage is predominantly obtained by amplifying the noise produced within the IFpassband of the IF-input stage.
4499606
not perceived by the user of the receiver. Sensitivity to switching is dependent on the rate of change of the received signal amplitude and on the modulation frequency of the received signal so that the system responds both to an overall reduction in received signal strength and to reduction in the strength of the high frequency portions of the received signal.
RECEPTION ENHANCEMENT IN MOBILE FM BROADCAST RECEIVERS AND THE LIKE William R Rambo assigned to SRI International p~oTaacao~
s~g~r¢~
4499609 SYMMETRICALLY CLAMPED FIBER OPTIC RECEIVER Willis M Muska assigned to International Telephone and Telegraph Corporation
c~p
I
A system for enhancing the quality of a signal received by a mobile FM transmitter by reducing the adverse effects of multipath transmission to the receiver. A pair of antennas is provided, and each antenna is arranged to receive transmitted signals that traverses a different path. The signal produced in the receiver by one antenna is compared with a reference threshold and when the amplitude of the signal falls below the reference threshold, the receiver switches to the other antenna. The signal amplitude is sensed in a high frequency portion of the receiver, i.e. before detection or demodulation, so that switching between antennas occurs rapidly and is normally
................ ,2a
~
zz
........... Fa4
z6
k
h
¢oh:¢~.
~.z- ~ - ~ le
~ ¢pRco r j
In a fiber optic receiver of the type comprising a photodetector, a preamplifier, a postamplifier and a voltage comparator for quantizing the output to a logic level signal, the improvement comprising symmetrical clamp means interposed between said postamplifier and said voltage comparator.
F o r information about P A T S E A R C H "
Pergamon InfoLine Inc. 1340 Old Chain Bridge Road McLean, Virginia 22101 USA Telephone (703) 442-0900 Telex: 90-1811
Pergamon InfoLine Limited 12 Vandy Street London EC2A 2DE England Telephone (01) 377-4650 Telex: 8814614
Pergamon Press Canada Ltd 150 Consumers Road, Suite 104 Willowdale, Ontario Canada M2J IP9 Telephone (416) 497-8337