General Research of Electronics, Inc.

Koichi Kazami

Kazuyoshi Imazeki

A novel apparatus is provided for facilitating the transfer of signals from a computer for the external setting of reception frequency parameters and other operating conditions of a radio receiver having a memory which is programmable according to data in the form of an electric pulse signal. The apparatus includes an interface circuit operatively coupled between the computer and the memory of the receiver. The interface circuit converts respective signal levels of the data into the electric pulse signals enabling data transfer and communication between the computer and the memory of the receiver. An improved flat-type, reversible connector is used between the interface circuit and the receiver. The connector has upper and lower surface portions, and is operatively coupled to a receptacle in the receiver. The connector has pairs of vertical connector conductors, each individual vertical conductor of each pair being connected to each other, within the respective surface portions and are arranged so that the mutually connected pair of conductors are positioned at both sides of a center conductor. The receptacle has contacts adapted to simultaneously contact the conductors on either of the surface portions of the connector, respectively. The contacts of the receptacle are connected in the same manner as the conductors of the connector, wherein the connector can be inserted into and connected to the receptacle in a reversible manner.

System for programming a radio receiver

A system for externally setting reception frequency parameters of a radio scanner having a memory which is programmable according to data in the form of an electric pulse signal generated according to a protocol by a computer. The system includes a computer, a stereo phone plug connected to the RS-232 port of the computer, and a scanner stereo phone jack which can receive both of the stereo phone plug and a monaural ear-phone plug. The stereo phone plug has a common electrode, a first signal electrode and a second signal electrode. The second signal electrode carries the data from the computer to the scanner. The stereo phone jack has a common electrode, a first signal electrode and a second signal electrode. The common electrode, the first signal electrode and the second signal electrode of the stereo phone jack are adapted to be connected to the common electrode, the first electrode and the second signal electrode of the stereo phone plug, respectively, when the stereo phone plug is inserted into and connected to the stereo phone jack. A level converter circuit is provided between the computer and the scanner and is connected to the second signal electrode of the stereo phone jack for converting the signal level of the data from the second signal electrode and the common electrode of the stereo phone jack to the level of the electric pulse signal which is suitable to write the program to the memory of the scanner.

System for programming a scanning radio

In a radio of the type having a selectively operable transmitter portion and an associated receiver portion for two-way communication, such as a CB radio, plus an auxilliary receiver for reproducing auxilliary audio signals, such as an AM/FM radio, a system is provided for automatically interrupting the audio signal output of the auxilliary receiver whenever the transmitter portion is operated. When the transmit/receive switch is in the transmit position, an auxilliary electronic switch interrupts the audio output of the auxilliary receiver by by-passing to ground the audio signal input to the audio amplifier section of the auxilliary receiver.

Automatic switching system for a combination transceiver-auxilliary

A variable impedance circuit is included between the antenna and the RF amplifier stage of a radio receiver portion of a transceiver and is responsive to a phase-inverted and amplified AGC signal to automatically protect the receiver from breaking down or otherwise malfunctioning when it receives an over-input or excessive input signal level. When the input signal level to the receiver is at the typical operating level, the circuit provides a substantially infinite impedance to ground so as not to interfere with signal transmission from the antenna to the input stage and the successive stages. The impedance to ground of the circuit decreases as the input signal level increases and, when an excessive input signal level sufficient to cause receiver breakdown or malfunction is applied to the circuit, the impedance to ground of the variable impedance reaches an almost zero level, thereby shunting to ground and thus harmlessly dissipating the excessive signal level input to the receiver before it can burn out or otherwise damage the input or subsequent circuitry or cause a malfunction thereof.

Automatic overload protection system

A system is disclosed for generating a plurality of preselected frequencies in a radio frequency device such as a receiver, transmitter or transceiver. It comprises means for generating a first reference signal having a predetermined frequency and means, including at least two voltage controlled oscillators (VCO), a mixer, a programmable frequency divider, and a switch, for generating a second reference signal, with the mixer being coupled to the first reference signal generating means and being selectively coupled on one of the VCO's by the switch to generate an output signal having a frequency corresponding to the difference between the frequency of said first reference signal and the frequency of the selected variable-frequency oscillator. Means are coupled to the first reference signal generating means and to the second reference signal generating means for comparing the first and second reference signals and developing a control signal which varies systematically in accordance with the frequency difference between the first and second reference signals, with the control signal being applied to both the VCO's to vary the oscillation frequencies thereof until the frequency of the second reference signal is substantially equal to the predetermined frequency of the first reference signal, whereby the output signal of the selected VCO has a frequency which corresponds to one of the plurality of predetermined receiver frequencies as selected by both the programmable frequency divider and the VCO selected by the switch.

Tuning system

A system is disclosed for generating a plurality of preselected frequencies in a radio frequency device such as a receiver, transmitter or transceiver. It comprises two crystal-controlled reference signal oscillators. First and second controllable variable-frequency oscillators (VCO's), first and second mixers, and a programmable frequency divider, together generate first and second output signals, with the first mixer being coupled to the first crystal oscillator and to the first VCO to generate the first output signal having a frequency corresponding to the difference between the frequency of the first reference signal and that of the first VCO. The second mixer is coupled to the second crystal oscillator and to the second VCO to generate the second output signal which has a frequency corresponding to the difference between the frequency of the second reference signal and the frequency of the second VCO. A phase comparator is selectively coupled to the mixers by a switch for selectively comparing the first reference signal with one of the output signals and developing a corresponding control signal which varies systematically in accordance with the frequency difference therebetween, with the control signal being applied to both VCO's to vary the oscillation frequencies thereof until the frequency of the selected output signal is substantially equal to the predetermined frequency of the first reference signal, whereby the output signal of the corresponding VCO has a frequency which corresponds to one of the plurality of predetermined receiver frequencies as selected by both the programmable frequency divider and the mixer output signal selected by the switch.

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Tokyo, Japan

Koichi Kazami