Abstract: A beam of charged particles (e.g., an electron beam) from a charged particle source can be selectively applied to a pair of electrodes. For example, the charged particles can be electrons that are directed toward a first electrode when the charge difference between the electrodes is in one state and directed toward the second electrode when the charge difference between the electrodes is in another state. The electrodes are configured so that the beam of charged particles oscillates between the first and second electrodes.

Abstract: A random number generator. The random number generator includes a noise source, a circuit controlling random current consumption, and a circuit generating random bits. A noise voltage output from the noise source drives the circuit controlling random current consumption, which also generates a random control signal. The circuit generating random bits also includes a voltage-controlled oscillator, a plurality of frequency dividers, and a plurality of flip-flops. The voltage-controlled oscillator is controlled by both the noise voltage and the random control signal. The output of the voltage-controlled oscillator is input to the frequency dividers and the flip-flops to generate a random number.

Abstract: In a method of calibration of a voltage controlled oscillator (VCO), the VCO (100) provides an output signal which is used to drive a dividing oscillator (10) such as a relaxation oscillator (RO). The RO has at least two states, one in which the RO provides an output signal which has a first frequency that is related to the VCO output signal by a first ratio (e.g. 1/N) and one in which the relaxation oscillator provides a RO output signal which has a second frequency that is related to the VCO output signal by a second ratio (e.g. 1/(N+1)). By measuring the first and second frequencies (and knowing the relationship between the first and second ratios), the VCO frequency is calculated and stored (110). Several VCO frequencies can be calculated and stored for several applied voltages. As a result the VCO can be driven to any selected frequency in the calibrated range and can be used to provide an injection frequency for a radio.

Abstract: A tunable oscillator includes an input for receiving an input signal from a source of precision frequency such as a CMOS quartz crystal oscillator. The tunable oscillator converts the frequency of the input signal to a first current using a frequency to current converter. The current produced is proportional to a first capacitor, C1. The first current is replicated to produce a subsequent current using a current mirror structure. The subsequent current is then used to generate a periodic signal using a current to frequency converter. The output frequency of the current to frequency converter is inversely proportional to a second capacitor, C2. As such the output frequency of the tunable oscillator is tunable by changing the value of the capacitance ratio C1/C2. The invention is suitable for applications that require a precision tunable source of frequency such as automated test equipment (ATE) and electrical instrumentation.

Abstract: An injection-locked waveguide oscillator comprises a first diode (3) having a free-running fundamental frequency above the local cut-off frequency of the waveguide (1) and a second diode (4) having a fundamental frequency below and a higher harmonic above the local cut-off frequency. The first diode (3) may be an IMPATT diode and the second diode (4) a Gunn diode. The free-running fundamental frequency of the first diode (3) is close to the higher harmonic of the second diode (4) so that the second diode (4) injection-locks the first (3). Locking in the reverse sense is inhibited by the inherent loss in conversion from the higher harmonic to the fundamental in the second diode (4), thus avoiding the need for a circulator or isolator. The two diodes (3, 4) preferably are mounted in a common waveguide (1) for a simple compact structure.

Abstract: A radio frequency numerically controlled oscillator comprising N one bit adders each providing sum and carry outputs to one of N two bit registers. Sum, carry and frequency selection inputs are combined by each adder to form sum and carry outputs. These results are held by the associated register when triggered by a clock input. A fast parallel adder/latch is employed which has two stages connected serially to generate sums on opposite phases of a two phase clock.

Abstract: An oscillation generator providing a succession of oscillations repetitively and progressively varying in amplitude includes a feedback oscillator arranged to receive its operating voltage from a capacitor that is progressively charged from a periodically fluctuating voltage source by way of an SCR and a timing circuit arranged to progressively vary the timing during the fluctuation period of the source of firing signals applied to the SCR. The timing circuit includes a firing capacitor charged from a unidirectional source and semiconductor switches arranged, when the potential on the firing capacitor attains a predetermined level, to discharge the capacitor into the trigger electrode of the SCR. The time required for the potential on the firing capacitor to reach the predetermined level is varied by a saw-tooth generator that controls the charging potential for the capacitor.