Abstract: A variable frequency signal generator includes a phase locked loop having a variable frequency oscillator which has a control port to which a frequency determining signal is applied, the output of the oscillator being fed via a frequency divider to a phase sensitive detector where it is compared with a reference frequency signal, the result of said comparison being arranged to generate a comparison signal which is fed to a loop filter which is coupled to said control port; and the signal generator having a frequency control signal applied thereto and comprising a first path being arranged to adjust the division ratio of the frequency divider, and a second path including a combiner for combining said frequency control signal and said comparison signal to produce said frequency determining signal; and a calibrator for adjusting the relative characteristics of said first and second paths to compensate for effects arising from tuning sensitivity dependence on frequency of said variable frequency generator.

Abstract: An atomizing nozzle for use in a fluidized coating bed includes an elongated hollow tube defining a chamber therein, the tube including an atomizing end in fluid communication with the chamber and a supply end; an air supply port at the supply end in fluid communication with the chamber; a coating liquid supply port at the supply end, the coating liquid supply port being separated from the air supply port; and a flow control tube extending within the hollow tube between the liquid supply port and the atomizing end, for supplying the coating liquid to be atomized to the atomizing end, the flow control tube having an reduced diameter inner bore providing a controlled flow constriction to the liquid travelling from the liquid supply port to the atomizing end so as to supply the coating liquid from the coating liquid supply port to the atomizing end with a controlled flow constriction, such that there is no need to provide a metering pump or flow meter for each atomizing nozzle of the fluidized coating bed and co

Abstract: A low-noise frequency synthesizer comprises a low-noise oscillator, such as a crystal oscillator, a multiplier, a divider and a phase-locked loop and is adapted to provide an output signal which is a combination of the multiplied and divided frequency. Thus, a large number of frequencies are available as an output in small increments determined by the division ratio of the divider.

Abstract: A phase comparator accepts two streams of digital pulses, one being a reference signal and the other a test signal, and generates an output signal indicative of the phase difference. The phase comparator can be implemented as a four-state device or higher, and thus exhibits a wide phase capture range, i.e. multiples of 360.degree., and can provide a stable, predictable and linear output signal when the two input signals are in lock. It is therefore very suitable for use in a phase locked loop in which temporary wide variations in phase can occur.

Abstract: A frequency synthesizer produces a variable frequency output using a controllable oscillator and a variable frequency divider which form part of a phase locked loop. The integer division ratio of the divider can be altered during a division cycle to simulate a fractional divisor value. The phase noise or jitter which is caused by the step change in divisor value is removed by altering the divisor value in accordance with the terms of a plurality of sequences, each of which sums to zero and which represents successive rows in a Pascal's triangle. A cascaded sequence of accumulators is used to determine the starting instants of each sequence, and the length of each sequence is dependent on the number of delay lines used. Although only four accumulators are illustrated, more can be added to give any desired degree of phase noise cancellation.