Abstract: A synchronous rectification switching power source device accurately determines the timing of the turning off of a synchronous rectifier switching element regardless of the state of the load, and a synchronous rectification period is utilized to the maximum. The switching power source device is configured of a main FET connected to a primary winding of a transformer, a snubber circuit connected to the primary winding, a synchronous rectifier FET connected to a secondary winding of the transformer, a diode connected to the synchronous rectifier FET, a synchronous rectifier FET drain voltage detection unit, an output voltage detection unit, and a drive control unit. The drive control unit accurately determines the timing of the turning off of the synchronous rectifier switching element using a unit that detects the on/off state of the main FET, a variable pulse generator unit, a count value generated by a counter unit, and a threshold value.

Abstract: Implementations of differential variable capacitance systems are disclosed.

Abstract: A TV tuner includes an Ultra High Frequency (UHF)/Very High Frequency (VHF) tracking filter, an UHF/VHF matching circuit and a single conversion Tuner IC. The UHF/VHF tracking filter includes a first Low-Temperature Co-fired Ceramics (LTCC) inductor, a first varactor diode and a fine-tune capacitor electrically connected to determine the maximum gain frequency of the UHF/VHF tracking filter. The UHF/VHF matching circuit includes a second LTCC inductance, a second varactor diodes and a fine-tune capacitor electrically connected to determine the maximum gain frequency of the UHF/VHF matching circuit.

Abstract: Disclosed herein is a system for the variable attenuation of broadband differential signals. An exemplary system of variable attenuation of broadband differential signals includes attenuation devices arranged such that an attenuation device on the positive side of the differential signal has a corresponding attenuation device on the negative side of the differential signal with both of the corresponding attenuation devices on the same semiconductor die.

Abstract: A voltage controlled oscillator (VCO), suitable for use in a frequency shift keying (FSK) system. The VCO device comprises a switching varactor unit, having a first terminal and a second terminal, wherein the switching varactor unit produces a capacitance, according to a frequency-selection voltage. A VCO core has a first output terminal, a second output terminal complementary to the first output terminal, and an input terminal. Wherein, the switching varactor unit is coupled in parallel with the VCO core at the first output terminal and the second output terminal to produce a capacitance effect with respect to the capacitance, so as to adjust a frequency constant ?{square root over (LC)} of the VCO core.

Abstract: The present invention provides a means for improving the sensitivity and selectivity of a car radio receiver. The variable inductance LC resonant circuit comprises: a amplifier 53 having enough high input impedance and enough low output impedance, a inductive element 51 connected a terminal to the input of said amplifier 53 and the other terminal to the output terminal of said amplifier 53, and a capacitive element 52 connected a terminal to the input terminal of said amplifier 53 and the other terminal to the ground. The proposed technique alters the parallel resonant frequency by varying an equivalent inductance 51, 53 seen from the condenser 52 side, wherein the equivalent inductance 51, 53 varies associated with the gain of said amplifier depending on the frequency control voltage from the PLL synthesizer to the terminal 54.

Abstract: A frequency translating device (FTD) includes at least one mixer diode connected to down-convert a radio frequency (RF) to an intermediate frequency (IF) and to up-convert an IF to an RF and a source of direct current (DC) bias that is connected to the mixer diode. The source of DC bias provides DC bias to the mixer diode that moves the voltage applied to the mixer diode closer to the threshold voltage of the mixer diode. The mixer diode is turned on in response to the DC bias and a local oscillator (LO) drive. Because DC bias is applied to the mixer diode, the peak to peak voltage range of the LO drive can be reduced, thereby reducing the voltage-dependent capacitance of the mixer diode, causing the FTD to exhibit improved reciprocity. The FTD can be used in a three-pair measurement system to determine the conversion response of another FTD.

Abstract: Linearizer circuitry is disclosed for providing control signal outputs to operate a controllable attenuator throughout a relatively large dynamic range while maintaining a relatively consistent return loss. Preferred embodiment linearizer circuitry provides a series control current and a shunt control current for coupling to a PIN diode attenuator, such as may be configured in a ? network or a T network. Preferably, differential pairs are utilized in providing each of the control current outputs.