Abstract: A circuit receiving a degraded synchronous pulse signal which has missing pulses and phase-shifted pulses, and producing an output signal similar to and at a constant phase angle with the input signal, in which the missing pulses have been replaced and the phase-shifted pulses shifted to the correct relative position. Provision is made for adjusting output signal frequency to long term drift in input signal frequency.

Abstract: Apparatus for producing an indication of the value of an unknown capacitance or inductance, which employs a variable frequency oscillator producing a sinusoidal output which is fed through a resonant circuit comprising a reactive circuit element of known value selected to attain resonance with the unknown reactor within the oscillator frequency range. A phase detector measures the phase shift between oscillator output voltage and output current, and its direction and supplies a phase shift signal specifying this information to a controller which supplies a frequency control signal to the oscillator. The controller varies the frequency control signal responsive to the phase shift signal to eventually reduce phase shift to 0.degree. or other predetermined value indicating the resonance condition in the circuit.

Abstract: Apparatus for measuring a dimension of a specimen whose image is projected by an optical system into a television camera or other light scanner, by forming the ratio of the time required to scan across the unknown dimension, with the time required to scan across the image of a reference dimension. The reference dimension is the width of an object placed in a focal plane of the optical system other than the focal plane in which the specimen having unknown dimension to be measured is placed.In a preferred embodiment, the apparatus includes a variable frequency oscillator which performs the measurements for the times required to scan these two dimensions. A feedback loop adjusts oscillator frequency so that the number of oscillations during the scan of the reference object equals the number stored in a register which can be altered only manually. This preferred embodiment can be calibrated by placing an object of known dimension within the field of view reserved for the specimen.