A cordless communication system includes a plurality of cordless communication devices, a plurality of connection units which couple the cordless communication devices and communication lines, and a control unit which controls connections between the connection units and the cordless communication devices. The control unit includes a retrieval range specifying part for specifying idle channel retrieving ranges within which connection units which are idle respectively retrieve idle channels so th...

A security device for protection against pickpockets comprising a clamp intended to be releasably clamped on a top edge of a pocket and connected to a card-size casing by a flexible connecting element is disclosed. The card-size casing is adapted to be received in a compartment inside a purse which, in turn, is received in the pocket such that pulling the purse out of the pocket causes a lock bolt on the clamp to tightly secure the clamp to the pocket. A pull rod is movably fastened in the casin...

An on-board monitoring system for an automotive emission catalyst [having] has (i) a test chamber remote from the automobile's engine exhaust gas stream; (ii) [means] apparatus for supplying the chamber with sampled exhaust gases sequestered from said stream; (iii) a single hydrocarbon sensor exposed to the exhaust gas in the chamber to render a signal responsive to the concentration of hydrocarbon in the chamber; and (iv) [means] apparatus for comparing the sensed signal with a reference signal...

A locking arrangement with built-in alarm mechanism utilizing a contact between portions of a split bolt arrangement as the prime security measure is described. Correct sequencing of both the locking and unlocking actions is required to prevent alarm. Two realizations are described: a self-contained unit for building doors; and an automobile unit with central alarm, alarm sensors for ignition and other locations subject to tampering (hood, trunk, battery), and a set resistance method to prevent ...

The noise blanker of a conventional FM radio is inhibited for several seconds upon closing of the receiver's squelch gate. Following the inhibit period, the blanker is reactivated and again inhibited for the full period upon a subsequent squelch gate closing. Thus, the blanker is inhibited for those signal conditions in which its operation would degrade the overall intelligibility of the processed signal as determined by the squelch control setting.

Disclosed is a millimeter wave integrated circuit balanced mixer including wo signal ports, a local oscillator and an input signal port, coupled to a pair of solid state millimeter wave mixer diodes by means of an image guide 3db hybrid signal coupler and a pair of mixer cavities formed from a wafer of boron nitride whose bottom surface is metallized and soldered onto a metal substrate having a metal surface defining an image plane. The signal coupler consists of two curved lengths of boron nitr...

An automatic gain control circuit for an AM receiver uses a signal having the same wavelength but reversed in phase with the signal in the antenna circuit. A variable resistance attenuator element such as a biased FET or PIN diode is used in the external antenna circuit having a winding to selectively attenuate the input signal to the tuning circuit including a secondary winding. Gain control is performed in an analog manner with respect to the input signal of the external circuit.

A radio receiver receives a transmitted high-frequency signal which is mixed within the receiver with a local-oscillator-frequency signal to form an intermediate-frequency signal, which in turn is converted into an audio-frequency signal. A plurality of indicator elements are arranged in a row to form a quasi-analog channel indicator, each indicator element of which is associated with a respective one of the selectable channels. A multi-channel oscillator furnishes the requisite local-oscillator...

A multiple frequency RF modem includes a frequency synthesizer for providing local oscillator signals to double balanced mixer circuits in both the transmitter and receiver sections. To test the frequency synthesizer, the synthesizer is set to produce a local oscillator signal having a nominal frequency of 3 IF. The transmitter RF filter is tuned to suppress all harmonics and sidebands other than the 4 IF sideband. A ganged set of switches is employed to connect the transmitter output directly t...

A system for determining the location of the sinking of a vessel by providing a seaworthy box that is automatically ejected from the vessel at the time of sinking and that has a battery aboard the box for powering a radio transmitter that sends distress signals that enable a rescue vessel to locate the ejected box. The system employs a water-activated release mechanism and a stationary box with which the ejected box mates. When the release mechanism operates the box is ejected and at the same ti...