Abstract: A crystal oscillator having a crystal filter with multiple crystals in a ladder configuration, resonant at a desired operating frequency. An oscillatory signal loop feedback path includes a voltage controlled phase shifter operable to shift the phase of the signal in the feedback loop in response to an applied control voltage. The feedback loop also includes a loop phase shift circuit to ensure that the feedback signal is a multiple of 360°, and a band pass mode selection circuit for eliminating unwanted frequencies.

Abstract: A dielectric resonator encased within a pressure enclosure establishes the operating frequency of a microwave circuit. The enclosure is supplied with a pressurized gas and the pressure within the enclosure is varied as a function of the deviation of the operating frequency from a desired value. For more precise control the enclosure is preferably immersed in a cryogenic cooling system.

Abstract: Multiple resonator stages are connected in series to form a closed loop. Each of these cascaded resonator stages includes at least a high frequency resonator and an amplifier. The amplifier amplifies the output of the high frequency resonator. Each stage also includes a power divider connected to the amplifier output. The power divider has at least two outputs. One of the two power divider outputs serves as an output of the oscillator formed by the cascaded resonator stages. The other output of the power divider is connected to the input of the next high frequency resonator stage. The oscillator further includes a phase shifter connected between two of the high frequency resonator stages to achieve a closed loop phase shift of N(360) degrees at the oscillator operating frequency, where N is an integer. The high frequency resonators may be acoustic resonators such as surface acoustic wave resonators (SAWR).

Abstract: A microwave oscillator with loop frequency conversion to and signal amplification at an intermediate frequency. A high-Q sapphire dielectric resonator is coupled in a frequency conversion loop between a pair of balanced mixers. One mixer comprises a downconversion mixer from an output frequency F.sub.0 to an intermediate frequency F.sub.IF, while the other mixer comprises an upconversion mixer from the intermediate frequency F.sub.IF to the output frequency F.sub.0. The frequency conversion loop additionally includes a low 1/f noise IF amplifier coupled between the mixers. The two mixers receive a local oscillator signal having a frequency F.sub.0 .+-.F.sub.IF from a microwave reference signal generator. In such an arrangement, an output frequency section and an intermediate frequency section is provided. The output frequency section includes the sapphire dielectric resonator and an output power divider while the intermediate frequency section includes the two mixers and the IF amplifier.

Abstract: An arrangement of crystal resonators that provides significantly reduced net resonator vibration sensitivity by arranging the crystallographic axes of some of the resonators to have antiparallel relationship, without regard to the acceleration sensitivity vector of any of the crystal resonators.

Abstract: A crystal-controlled oscillator exhibiting reduced levels of crystal-induced low frequency noise, vibration sensitivity and circuit temperature rise includes an amplifier or oscillator sustaining stage which is secured to a heat sink. A plurality of crystals connected with each other in a preselected electrical configuration are secured to a vibration dampening structure which extends from the heat sink, and the plurality of individual crystals are connected with the oscillator sustaining stage via a preselected wavelength section of coaxial cable. The coaxial cable wavelength may be varied to provide that the plurality of individual crystals operate at either series or parallel resonance.

Abstract: A low noise crystal controlled oscillator utilizes a single low impedance modular amplifier in conjunction with matching low impedance fixed element subcircuits to achieve predictable and repeatable frequency stability. A low component count enhances circuit reliability.

Abstract: An oscillator circuit utilizing multiple (two) quartz crystal resonators as the frequency controlling elements in a novel circuit arrangement. The use of two crystal units increases the oscillator circuit signal transmission group delay by a factor of 2 to 3 and effects an estimated 6 dB reduction in oscillator output signal phase noise sideband level at carrier offset frequencies less than the resonator half-bandwidths. The degree of resonator tracking required is made practical with the use of temperature controlled SC-cut resonators. In addition, the oscillator circuit is configured so that equal, correlated output signal currents can be extracted from each resonator through individual load circuits, thereby increasing available oscillator output signal amplitude by 2:1 and reducing the net effect of uncorrelated load circuit additive noise by 3 dB.

Abstract: A narrow band, voltage controlled crystal oscillator having a linear frequency versus tuning voltage response. The oscillator uses a composite resonator in a novel circuit configuration with a resulting improvement in oscillator output signal frequency stability.

Abstract: An impulse generator apparatus for a high resolution Chirp radar utilizing a fast settling time VHF oscillator in combination with a digital counter and a low phase distortion output filter to provide a sharp gated sinusoid impulse waveform to excite the receiver dispersive delay line.

Abstract: A linear sensitivity voltage controlled crystal oscillator of the type including a resonator coupled to a negative resistance generator. The resonator comprises a crystal connected in series with a voltage variable capacitance device. The response of the resonator is linearized by the addition of an inductance across the voltage variable capacitance device. A resistor is shunted across the crystal to prevent oscillation at spurious resonances of the resonator.

Abstract: A frequency multiplier circuit utilizing a zero-crossing detector for producing a square wave at the frenquency of the input signal to generate harmonics of the input frequency. The square wave is filtered to generate a signal of a predetermined harmonic.