Abstract: A temperature and frequency variable gain attenuator comprises a temperature variable attenuator and a temperature variable filter network whose resistances changed to c generate different responses that vary over temperature and frequency. At least three different thick film thermistors are used, with two of these used on the attenuator and a third one used on the filter network. The temperature coefficients of the thermistors are different and are selected so that the attenuator and filter network attenuation change at a controlled rate with changes in temperature while the impedance of the gain equalizer remains within acceptable levels. Substantially any temperature coefficient of resistance can be created for each resistor by properly selecting and mixing different inks when forming the thick film thermistors. Furthermore, the attenuator can have either a negative temperature coefficient of attenuation or a positive temperature coefficient of attenuation.

Abstract: The present invention is an absorptive-type cable temperature and frequency equalizer that offsets changes in the gain of the other circuit components cables with increases in temperature and/or frequency. The equalizer comprises a temperature variable filter network having component values and a temperature coefficient of resistance that vary over temperature and frequency to produce a desired response. The temperature and frequency equalizer has at least one thick film thermistor connected in series with a quarter wavelength transmission line. The thermistor absorbs forward and reflected signals at lower frequencies.

Abstract: A temperature and frequency variable gain attenuator comprises a temperature variable attenuator and a temperature variable filter network whose resistances changed to c generate different responses that vary over temperature and frequency. At least three different thick film thermistors are used, with two of these used on the attenuator and a third one used on the filter network. The temperature coefficients of the thermistors are different and are selected so that the attenuator and filter network attenuation change at a controlled rate with changes in temperature while the impedance of the gain equalizer remains within acceptable levels. Substantially any temperature coefficient of resistance can be created for each resistor by properly selecting and mixing different inks when forming the thick film thermistors. Furthermore, the attenuator can have either a negative temperature coefficient of attenuation or a positive temperature coefficient of attenuation.

Abstract: The present invention is an absorptive-type cable temperature and frequency equalizer that offsets changes in the gain of the other circuit components cables with increases in temperature and/or frequency. The equalizer comprises a temperature variable filter network having component values and a temperature coefficient of resistance that vary over temperature and frequency to produce a desired response. The temperature and frequency equalizer has at least one thick film thermistor connected in series with a quarter wavelength transmission line. The thermistor absorbs forward and reflected signals at lower frequencies.

Abstract: A single reference tone/frequency-based control scheme adjusts the DC bias voltage and modulation signal drive level to an external X-cut lithium niobate Mach Zehnder modulator, in accordance with phase quadrature components of the output of the single tone frequency generator. A pair of phase quadrature feedback loops are coupled through a loop filter of a common feedback path electo-optically coupled to monitor the optical output of the laser modulator. Quadrature-phase (Q) and in-phase (I) frequency components are respectively coupled to respective Q and I channel phase detectors, coupled to synchronous demodulators for the Q and I channel feedback loops. The phase detectors produce respective error voltages that close Q and I channel feedback loops and control the optical extinction ratio and DC bias voltage of the modulator.

Abstract: A phased array antenna has a spatially periodic array of tapered pitch helical antenna elements disposed on a first side of a panel, and RF interface circuitry on a second side the panel. For a ‘pseudo’-monopulse tracking mode of operation, single bit, digitally controlled phase shift elements of the RF circuitry impart sequentially different amounts of phase shift to the energy derived from the spatial sections of the antenna elements. This causes a sequential electrical tilting of the beam pattern of the array in a plurality of respectively different directions relative to boresight. For each sequential tilt of the beam pattern, signals representative of the energy received by each of plural quadrants of the array are summed and stored.