Abstract: A synthesizer produces step frequencies by multiplying the frequency of a reference oscillator and stimulating an SRD comb frequency generator, then adding or subtracting a reference frequency. The selected step frequency can be placed on either side of each picket of the comb's spectrum. A fine adjustment frequency is then added in a translation oscillator. The fine frequency component can also be placed on either side of the selected step frequency.Frequency dividers, which would result in noisy final outputs, are not employed. Instead, the frequency of a reference signal is multiplied up in a narrowband channel to serve as a local oscillator, and the VCO signal frequency is reduced by heterodyning it down from its ultra-high frequency. The down-converted difference frequency is compared as to phase with the reference oscillator. The loop gain and bandwidth are so high in the phase lock loops that output noise is low and switching time is fast.

Abstract: Narrow amplitude calibrated pulses are injected into the RF input ports of microwave receivers such as those used for interference and intensity measurements to gain calibrate the receivers. The upper frequency limit of the prior art calibration source is greatly extended by frequency modulating the pulse generator to obtain pulses that vary in repetition rate between 95 and 105 MHz so that beginning with the tenth harmonic, a continuous band of pulses of predetermined amplitude sweeps from 950 MHz up to approximately 18 GHz.

Abstract: Receivers with bilateral input stages, such as microwave receivers that are used in noise and RF interference measuring instruments, are gain calibrated in the field by injecting a fixed level calibration signal at the IF frequency into the circuitry between the first mixer and first IF stage. The calibration signal is thus passed through the first mixer where it is converted to the tuned RF frequency and then to the RF input port where its power is measured to control a variable attenuator in series between the calibration signal source and the receiver IF stages. The attenuator is thus automatically adjusted so that the level of the calibration signal entering the IF stage balances the losses in the receiver front end, and a variable gain IF amplifier may be adjusted to produce a predetermined level on the receiver output meter to properly calibrate the instrument.

Abstract: Circuitry for generating pulses with extremely accurate widths. Clock signals, from a precision crystal controlled oscillator, control an input flip-flop which fires a one-shot multivibrator adjusted as closely as possible to the desired pulse width. The one-shot output is coupled to an output flip-flop controlled by the crystal controlled clock so that the width of the output pulse becomes an exact multiple of the clock period.