Abstract: A communication system includes a mobile station, a plurality of base stations and a central terminal. Each base station converts RF signals from the mobile station to AF signals. The AF signals are carried over a balanced line to the central terminal. Each base station generates a DC voltage signal whose level is representative of the level of its received RF signal. The central terminal includes means to monitor DC current levels, from each base station, on the balanced line and select that base station producing the highest DC current.The unique interface circuit senses the base station generated DC voltage, which is referenced to a fixed ground potential, and produces a corresponding current which is referenced to a floating ground potential. This current is then coupled to the balanced line for transmission to the central terminal. The interface circuitry includes a DC to AC converter which converts the DC signal voltage to an AC signal.

Abstract: A coupler series connects in the power line to be monitored. Sensing circuitry within the coupler senses power flow in each direction of the power line, and produces D.C. signals representing the magnitude thereof. The D.C. signals appear at contacts on the body of the coupler.A housing is provided with a cavity for receiving the coupler. Contacts in the housing adjoin the cavity and are aligned to connect to the coupler contacts. A D.C. activated meter is mounted in the housing, and is electrically connected through a switch to the housing contacts.In operation, the coupler is series connected in the line and, when power is to be monitored, it is secured within the housing. By operating the switch, a user may monitor power flow in either direction down the line.

Abstract: An R. F. wide band amplifier is disclosed. It comprises a high impedance step up transformer at the input end, a wide band high impedance J-Fet attenuator connected to the step up transformer, a dual gate MosFet amplifier connected to the attenuator and a high impedance wide band step down transformer connected to the output of the MosFet. The output of the amplifier is taken from the stepped down side of the transformer.

Abstract: High frequency power transistor carriers are made by bonding a metalized ceramic base to a lead frame strip, cutting the lead frame strip to isolate the base and collector leads while still maintaining the transistor carriers in strip form, and subsequently gold plating the resultant structure. Transistor dice are then attached to each ceramic carrier, and each transistor carrier in the strip is then electrically tested. The individual carriers are then separated from the lead frame strip. The individual carrier has wide base and collector leads extending outward from the ceramic base for a substantial distance and then the base and collector leads are narrowed down. When the individual transistor carrier is used in combination with a hybrid assembly, a reduction in lead inductance and total hybrid package size is obtained while exact carrier placement relative to the hybrid assembly is not required.

Abstract: Signals over a data channel are detected for the presence of a non return to zero, psuedo random coded bit stream which is synchronized to a clock frequency and contains submultiple harmonics thereof. The submultiple frequencies occur at discrete integer intervals ranging from 1/2 to 1/N of the clock frequency, where N is an integer dependent upon the data generation scheme.The detection system employs an improved quadrature detector which compares narrow width window pulses, derived from the clock signal, which occur in quadrature to the encoded bit stream, with narrow width transition pulses generated at data signal transition time. In response to the synchronous occurrence of a given number of window-transition pulses per time interval, the quadrature detector produces an inhibit signal, thus indicating the absence of a detected data stream.

Abstract: A microphone which consists of a speaker having a base resonant frequency, a suppression circuit for reducing the frequency response of the speaker at the base resonant frequency, and a high pass filter for reducing the base frequency response of the speaker is disclosed. The speaker creates electrical signals in response to sound waves received and the suppression apparatus reduces the relative magnitude of the electrical signals having frequencies substantially equal to the base resonant frequency of the speaker. The high pass filter reduces the magnitude of all electrical signals having frequencies below a predetermined frequency, and thus a desired microphone frequency response is obtained.A communications system which uses a receiver to drive a speaker in one mode of operation and uses the speaker as a microphone followed by a compensation network and a transmitter in another mode of operation is also disclosed.

Abstract: A fast responding, low jitter, digital phase lock loop which is especially suited for synchronous, non return to zero, digitally encoded clock recovery applications.Both leading and trailing transitions of the digital waveform triggers a monostable multivibrator which generates well defined transition pulses. These pulses are fed to a phase comparator, where they are simultaneously compared with the output of a programmable frequency divider, whose input couples to a reference frequency oscillator. The detected phase relationship between the two compared signals causes the divider to either increase, or decrease its division factor and thereby readjust the relative phase relationship between the divided signal and the digital signal until they are in phase lock.During an absence of digital signal input, provision is made for selecting a third division factor whose value is between the first and second factors.

Abstract: A pager antenna system having two conductive containers which act as radiators and form a dipole antenna is disclosed. A metallic coil constructed of tubular material is positioned between the conductive containers and has a first end electrically connected to one of the containers. The tubular coil forms part of an antenna impedance matching network and also serves as a conduit for wires which interconnect circuit components located in each of the conductive containers. High frequency isolating chokes are connected in series with the interconnecting wires emerging from a second end of the tubular matching coil and prevent these wires from forming low impedance RF paths between the conductive containers. By making the RF impedance matching coil also serve as a conduit for low frequency interconnecting wires, fewer parts are required, the interconnecting wires are shielded from external influences, and low Q chokes can be used by connecting them across points which have a low RF impedance therebetween.

Abstract: An improved gain antenna which is vertically mounted to a horizontal ground plane is disclosed. The gain antenna substantially consists of a radiating conductor having first and second ends and a centrally located feed point, and phasing apparatus electrically connected to the conductor for producing a predetermined current distribution. The phasing apparatus produce shortened out of phase current sections along the length of the conductor. Centrally feeding the gain antenna results in an improvement in the bandwidth and input impedance. The conductor consists of a linear section of coaxial cable which extends vertically from the horizontal ground plane to approximately the central feed point and a solid conductor rod which extends vertically upwardly from the central feed point. Current phasing apparatus having improved bandwidth and reactance characteristics are also described.

Abstract: An oven having a thermistor controlled proportional heating system is compensated for ambient temperature variations by using a second thermistor sensing ambient temperature and connected in series with the control thermistor in an electrical bridge circuit. The control thermistor is mounted within the oven and substantially monitors the oven temperature while the ambient thermistor is located outside the oven and monitors ambient temperature. The electrical bridge circuit produces a temperature control error signal which is amplified and applied to a heater winding which is wrapped around the oven. The ambient thermistor produces a resistance variation in the electrical bridge circuit which modifies the temperature control signal such that a predetermined point inside the oven is held at a constant temperature regardless of any ambient temperature changes.

Abstract: A method and apparatus for a thermal printer head which uses individual heater elements as switching devices is disclosed. The printer head consists of an array of individual resistors each capable of causing a dot to print on thermally sensitive paper. The use of heater elements as switches reduces the total number of lead outs required for the printer head. A system that uses such a thermal printer head is also disclosed. The individual resistor heater elements have a voltage-current switching characteristic which enables them to be used as switching devices in addition to their function as heating elements.

Abstract: A pneumatic machine for cutting flexible tubing and inserting the cut pieces onto a printed circuit board is disclosed. The machine unwinds a spool of tubular material, cuts a predetermined length off the end thereof and inserts the cut length onto a printed circuit board. The sequencing and timing relationship between the feeding, cutting, and inserting steps is controlled by a cyclic sequencing apparatus which is activated by a foot switch.A machine for forming and inserting eyelets into a printed circuit board is also described. The eyeleting machine unwinds a spool of tubular solderable material, cuts off a length of the tubular material, and inserts the cut tubing into a printed circuit board hole and then forms a shoulder on both ends of the inserted tubing. The sequencing and timing between the feeding, cutting, and inserting operations is controlled by a sequencing apparatus which is activated by a foot switch.

Abstract: A dual-coupled monolithic crystal element is connected to a crystal filter to bypass signals of a predetermined frequency which are applied through the filter. The shunt connected crystal element can be used with a bandpass filter to bypass frequencies at which the crystal filter produces a spurious response so that such frequencies will not appear in the filter output. Alternatively, the monolithic element can be selected to bypass frequencies adjacent the edges of a band which is selected, to provide sharp attenuation at the edges of the band thereby providing a very steep filter characteristic. The monolithic element includes a flat quartz wafer with electrodes provided on both sides at two separate portions of the wafer to form two resonant portions coupled through the wafer. The electrodes of one portion are connected across the input or the output of the crystal filter, and both electrodes of the other resonating portions are grounded.

Abstract: A circuit for disabling, or shutting down, the transmitter of a mobile telephone unit when the unit is not connected to another party is disclosed. When such a "wild" mobile is sensed, a sequence of idle and seize audio tones are sent and transitions therebetween are counted. When a specific number of counts are counted a disable signal is developed. The counter is continually reset and does not count when the handset is on hook. When the handset is off hook and the mobile is talking to a party voice falsing of the counter is prevented by a timer circuit.