Abstract: An adaptive interference reduction system for removing cross talk from a dual polarization system comprising a first adjustable filter for varying the phase and the weight of a first input signal, a second adjustable filter for varying the phase and the weight of a second input signal, a first adder for adding this first input signal and the weighted and phase adjusted output from the second adjustable filter, a second adder for adding the second input signal and the weighted and phase adjusted output from the first adjustable filter, a first noise-to-signal measuring device for generating a signal proportional to the noise-to-signal ratio in the output signal from the first adder, a second noise-to-signal measuring device for generating a signal proportional to the noise-to-signal ratio in the output signal from the second adder, and a dither-type control logic for dithering in-phase and quadrature square-waves in accordance with the signals generated by the first and second noise-to-signal measuring devices

Abstract: A compound acoustic apparatus includes a radio receiver and a magnetic tape player which are adapted to be mounted on the interior panel such as the dashboard of an automobile. The apparatus includes a main unit formed with an opening in its front side, which is adpated to receive a tape cartridge which cooperates with the player and an operating unit having operating buttons, knobs and indicators of the player and the receiver mounted thereon and which is formed with a slot of a commensurate size as the cartridge receiving opening. The main unit and the operating unit are disposed on the opposite sides of the interior panel, which is also formed with a slot which provides a communication between the cartridge receiving opening and the slot formed in the operating unit.

Abstract: A capacitive signal dependent upon a quantity being measured is produced by capacitive sensors of a radiosonde. An oscillator in the radiosonde has an output frequency, controlled by the capacitive signal, in the order of 1 to 10 MHz. The output frequency of the oscillator is divided by a factor of 2.sup.7. A high frequency transmitter in the radiosonde is frequency modulated by a frequencyf.sub.M1 =f.sub.M0 /dwherein f.sub.M1 is the output frequency of the divider and f.sub.M0 is the input frequency of the divider.

Abstract: A data transmission system comprising a transmitter producing a high-frequency carrier modulated with data and swept in a repetitive time pattern over a wide frequency range. The modulation of the carrier is so controlled that a characteristic of the data signal modulation has a predetermined relationship with respect to the repetitive sweep time pattern. The system receiver comprises a narrow-band IF channel coupled to the output of a mixer arranged to receive the incoming swept-carrier signal and a correspondingly-swept local oscillator signal. The sweep control signal for the local oscillator is developed by a circuit coupled to the mixer output and responsive to the data modulation on the IF signal.

Abstract: A directional radio system with single sideband operation for the transmission of a carrier frequency modulated single sideband signal in the intermediate frequency plane. In the transmitter, the intermediate frequency signal which contains the base band is provided with at least two pilot signals of different frequency and in the receiver a tuning criterion for the mixing oscillator of the receiver is derived from the frequency spacing of the received pilot signals and from the frequency shift of the received pilot signals produced by transmission of same over the radio links.

Abstract: A radio receiver having a tunable RF stage with an electrically tunable inductor is disclosed. The tunable inductor consists of a magnetic device with a core whose degree of magnetic saturation is controlled by various control currents. A phase lock loop with a programmable frequency divider responds to inputs from a tuning control means and provides a local oscillator signal to a mixer in the radio receiver while also providing a control current to the magnetic device, defined herein as Current Controlled Inductor (C.C.I.), which is directly related to the frequency of the local oscillator signal supplied to the mixer. Each time the radio receiver is tuned to a different input frequency by changing the frequency of the local oscillator signal, a predetermined reference current is applied to the C.C.I. before a new control current corresponding to the new local oscillator frequency is applied. This results in always tuning the C.C.I. in a single direction and therefore accurately setting the C.C.I.

Abstract: A frequency translating circuit such as an intermediate frequency circuit comprises a wide band transformer having a two-terminal secondary and first and second frequency passing filters coupled respectively to one and the other of the secondary terminals. Each of the filters is arranged to pass a different subband of frequencies within the wide band of frequencies passed by the transformer and to act as substantially a short circuit to the other frequency subband.

Abstract: A phase-locked loop (PLL) circuit and a synthesizer tuner incorporating the PLL circuit where a second DC control signal is applied to the PLL voltage controlled oscillator to reduce the phase error output signal from the PLL phase detector to near zero volts and thereby improve the performance of the voltage controlled oscillator and the S/N ratio of the tuner. Various circuits are disclosed for deriving the above second DC control signal. Further improvement in the S/N ratio is effected by switching in a narrow capture range for the PLL circuit when the desired signal is received and when the PLL phase detector output is operated near zero volts. Also when the station is changed, detuning is detected to switch in a broader capture range.

Abstract: A lock detecting circuit of a phase locked loop, comprising a phase comparator for receiving a reference frequency signal and a signal being compared with the reference frequency signal, a charging/discharging circuit which is charge/discharge controlled responsive to the output of the phase comparator and either of the above described two signals, and a delay flip-flop responsive to the output of the charging/discharging circuit and in synchronism with the signal applied to the charging/discharging circuit for assuming one storing state for providing an output representative of the phase difference between the above described two signals.

Abstract: A muting range setting circuit for an FM receiver uses a pair of differential amplifiers. Each of the differential amplifiers employs the same transistors having like polarity with common input and output terminals. The output of the tuner AFC is compared with an input reference voltage in the differential amplifier circuit and the output representing the frequency deviation of the FM detecting circuit is applied to the gate driving circuit for control of the muting operation.

Abstract: A limiter circuit comprises a low-pass filter which passes only a modulation signal out of the modulation signal having pulsive noises superimposed thereon and circuit means for supplying the modulation signal extracted by the filter to current source circuits for a limiter differential amplifier to control the current source circuit for the limiter differential amplifier in accordance with a waveform of the input modulation signal applied thereto.

Abstract: A heterodyne phase lock system is disclosed having a plurality of oscillator circuits, a similar plurality of heterodyne (mixer-filter) circuits representing an input circuit, and a similar plurality of heterodyne circuits representing a control circuit, at least one of the oscillator circuits being a voltage controlled oscillator (VCO) circuit. The heterodyne circuits of the input circuit are cascaded, i.e., linked each to the other, successively, and the heterodyne circuits of the control circuit are likewise cascaded. Each oscillator is linked to a pair of heterodyne circuits, i.e., to one heterodyne circuit in the input circuit and to one heterodyne circuit in the control circuit, and applies a common output signal to said pair of heterodyne circuits.

Abstract: A combination VHF-UHF tuner includes a VHF tuner and a UHF tuner in which the VHF tuner has at least three tuning networks connected in a stage preceding a mixer and each constituted by first and second coils and a variable capacitance diode. The first coil in each of the tuning network is coupled to a switching diode for shortcircuiting the first coil for establishing a network operable to a high band VHF signal and for opening the first coil connected to the second coil for establishing a tuning network operable to a low band VHF signal. A band selecting circuit is provided for controlling the three tuning networks in such a manner that the three tuning networks are all operable to the high or low band VHF signal when the VHF channel is tuned in and that at least one of the three tuning networks is operable to the high band VHF signal while the remaining is operable to the low band VHF signal when the UHF channel is tuned in.

Abstract: A two-mode limited channel television receiver includes a memory address counter for scanning the locations of a limited position memory in response to generation of a channel number by a channel number counter. Channel numbers and corresponding tuning information may be programmed into and deleted from the limited location only memory. In the programmed channel mode, memory locations with programmed channel numbers are accessed in channel number order. In the skipped channel mode, only unprogrammed channel numbers are produced and displayed to the viewer. In a variation, all channel numbers, both programmed and unprogrammed are produced and displayed. Empty memory locations are automatically accessed when an unprogrammed channel number is generated.

Abstract: A method and apparatus for increasing the signal-to-noise ratio of a receiving facility for coherent frequency reception by arraying receiving systems using separate antennas for each, or one antenna for all systems. One system is operated with a carrier tracking loop to provide a first local oscillator frequency for the first and all other systems arrayed, with individual tracking loops in all other systems operated at IF for tracking out any phase differences due to separate group delays using an adjustable phase shifter for a second reference (REF. 2) to compensate for different group delays in the antenna and low-noise amplifier of each of the other systems. The second IF output of all systems are summed into the first system.

Abstract: An antenna tuning circuit of the type having a first variable capacitance diode connected in parallel with a coil to form a resonance circuit and a second variable capacitance diode through which the resonance circuit is connected to an antenna, in which the connection position of the first variable capacitance diode to the coil is adapted to be changed for the reduction in the image interference ratio. Reductions in the maximum capacitance and the ratio between the maximum capacitance and the minimum capacitance required for the variable capacitance diodes are also intended by the connection of a third variable capacitance diode to the antenna side of the second variable capacitance diode.

Abstract: A citizens band transmitter employing negative overall envelope feedback in the final RF stage obtains the feedback signal from a filter in the antenna coupling network which has a phase shift of 90 degrees or an odd multiple thereof at the radio frequency. A pair of detector diodes have their cathodes connected to opposite ends of filter and their anodes connected to a low pass filter to provide an envelope of the higher of the two voltages at either end of the filter in the coupling circuit in negative feedback to the modulating signal.

Abstract: A switching arrangement for VHF-UHF tuners is provided wherein changeover from VHF operation to UHF operation is accomplished by employing wiping action stator contacts and with a minimum of connections between the VHF and UHF tuners.

Abstract: An r.f. signal transmission line system in which a plurality of spaced apart A.C. power sources are respectively coupled by power combiners to a plurality of sequential segments of the transmission line for powering a group of spaced apart thru-powered r.f. signal amplifiers in series with each segment. Each power combiner includes a switching circuit for automatically disconnecting the source from the line segment in the event of failure of the source. Associated with stop-powered amplifiers between adjoining segments is an automatic switching circuit which converts the stop powered amplifier to thru powering in the event of loss of power to a line segment on either side of the stop-powered amplifier and which restores the amplifier to stop-powering upon restoration of the lost power.

Abstract: Tuning apparatus of the type including at least first and second tuners, such as AM and FM tuners, operable to be tuned over respective broadcast frequency bands. The tuning apparatus includes a dial scale calibrated in at least two sets of gradations to represent the particular frequencies in the respective frequency bands to which the tuners are tuned and an indicator movable across the scale to indicate the frequency to which a respective tuner is tuned. The apparatus comprises at least one first settable element associated with a corresponding frequency band to be set to a desired location along the scale and at least one second settable element associated with a different frequency band to be set to a desired location along the scale. Sensors are coupled to and movable with the indicator to sense each of the first and second settable elements as the indicator is moved across the scale.