Abstract: A telephone-line dedicating apparatus which is connected between an external telephone-line and a specified telephone-line utilization apparatus such as a telephone-set, facsimile machine or the like and which upon energization causes one or more other telephone-line utilization apparatus to be unable to function connected to said external telephone-line is disclosed. Specially, when said specified telephone-line utilization apparatus is a facsimile machine, any influence on said facsimile machine which is in use, due to noises from the other equipments connected to the same external telephone-line can be prevented.

Abstract: A telephone answering apparatus permits a called party to select between an automatic mode wherein a message is automatically played back to a caller without any action of the called party and a prenouncer mode wherein a message is played back to the caller when activated by the called party. The telephone answering apparatus includes a ring detector circuit connectable to an outside line and responsive to an incoming call on the outside line for producing a ring detected signal, a timer and driver circuit responsive to the ring detected signal for producing a playback signal and a manually actuatable answer switch. A mode switch capable of selecting one of the prenouncer mode and the automatic mode is connected to the timer and driver circuit, to the ring detector circuit and to the answer switch.

Abstract: A digital image exchange system comprises a data transmission line, at least one video RAM, at least one video signal generator for accessing data from the video RAM and for developing at least two video signals corresponding respectively to the accessed data, and at least one modulator for modulating the video signals to form transmitted signals in at least two different frequency bands to be transmitted on the data transmission line. At least one demodulator is coupled to the transmission line at a location remote from the modulator for demodulating the transmitted signals in each of the at least two frequency bands to form at least two corresponding video signals; and at least one video display device is operatively coupled with the demodulator for displaying visual images corresponding to the respective video signals.

Abstract: A radio receiver includes a noise blanking system comprising a switching circuit in the signal path which is responsive to a blanking signal for preventing passage of signals. A blanking signal producing circuit is in the signal path ahead of the switching circuit and is responsive to predetermined noise signals received by the radio receiver for producing the blanking signal. The receiver also includes an AGC circuit for producing a gain control signal and a signal strength meter coupled for response to the gain control signal. A linearity control system comprises a current controlling circuit responsive to a meter control signal for controlling the current flow through the meter so as to increase the range of linear response of the meter. A signalling circuit is coupled with the AGC circuit and with the current controlling circuit and is responsive to the gain control signal for producing the meter control signal.

Abstract: A removable rod antenna comprises a first fitting for rigidly coupling to a radio body; an elongate rod-like antenna body; a second fitting of complementary configuration for engaging the first fitting, and a retaining arrangement for holding the second fitting in captive relation on the antenna. Respective mating fastener portions are defined respectively on the first and second fittings for removably engaging each other in electrically conductive contact to thereby removably mount the antenna body to the radio body in electrically conductive contact with the first fitting thereon.

Abstract: In a pseudo-random communication system, a transmitter-generated encoded signal is to be correlated with a receiver-generated similarly encoded signal for recognizing synchronization of the transmitted and received signals in the presence of undesired received energy. The system comprises a spread-spectrum transmitter including at least two pseudo-noise generators for producing at least two pseudo-noise signals which are related in a predetermined fashion, a mixer for receiving and mixing the two pseudo-noise signals with respective carrier and information signals to produce an output signal, and apparatus for transmitting the output signal. The system also includes a spread-spectrum receiver comprising a correlator and a matched filter coupled in circuit to form a synchronization detector circuit for receiving and detecting the encoded output signal transmitted by the transmitter so as to recover the information therefrom.

Abstract: A linearity control system comprises a current controlling circuit responsive to a meter control signal for controlling the current flow through the meter so as to increase the range of linear response of the meter.

Abstract: A radar detecting system comprises an antenna for receiving radar signals, a sweep generator for producing a sweep signal over a predetermined range of frequencies and at a predetermined rate and a mixer for mixing the sweep signal with the received radar signal for producing intermediate frequency (IF) signals. A bandpass filter passes only those IF signals within a predetermined frequency band and a detector responds to the IF signals passed by the bandpass filter by producing corresponding output pulses. A control circuit is responsive to a pair of output pulses being produced for each of three successive cycles of the sweep signal and to both the first pulse and the second pulse of each pair of pulses occurring at the same time intervals respectively relative to the corresponding cycle of the sweep signal for producing a warning signal.

Abstract: A radio direction finding system comprises a receiving portion for receiving a radio signal and a direction determining portion coupled to the receiving portion for developing a direction signal corresponding to the direction of arrival of a received radio signal. A memory is also provided for storing direction data corresponding to the direction of arrival of at least one received radio signal, and a control circuit is coupled intermediate the direction determining portion and the memory for producing direction data corresponding to the direction signal for storage by said memory. In accordance with a further aspect of the invention, an indicator is provided for actuation by the control circuit to produce an observable indication of the direction of arrival of a received radio signal, and the direction finding system further includes an EPIRB detector portion for producing an EPIRB reception signal in response to reception of an EPIRB signal.

Abstract: A horn antenna comprises a horn of the type including a rectangular throat, a rectangular opening located in a plane parallel to and spaced part from the throat and having at least one dimension larger than a corresponding dimension of the throat, and four wall portions joining the throat and the opening. An electrically conductive member is disposed so as to define any one diagonal across the horn from and including the opening to and including the throat.

Abstract: A slide switch comprises a plurality of sets of aligned terminals, each set comprising at least a center terminal and two end terminals, one to either side of the center terminal and aligned along a common axis therewith, and a plurality of elongate slides respectively associated with the sets of terminals. The slides are of sufficient length to engage the center terminal and only one of the associated end terminals. An actuator mounts the slides for movement between a first position wherein the slides electrically couple each of the center terminals with one of its associated end terminals and a second position wherein the slides electrically couple each of the center terminals with the other of its associated end terminals. A light emitting element has a pair of electrodes and is responsive to a given voltage across the electrodes for emitting light.

Abstract: A dual frequency band radar detector responds to radar signals occurring within either of a first or a second range of frequencies. The detector comprises one or more antennas for receiving radar signals including radar signals occurring within the first and second ranges of frequencies. At least one pilot signal at a predetermined frequency is produced for modulating the received radar signals. The modulated signals produced in response to received signals in either of said first range of frequencies or said second range of frequencies are isolated. A detector is coupled in circuit for detecting the one pilot signal in these isolated and modulated signals and a control output signal is produced responsive to the detected pilot signal. Accordingly, the presence of a control output signal indicates the reception of radar signals occurring within at least one of the first and second ranges of frequencies.