An electronic locator for tracing the course of a metallic discharge line which is disposed underground. A reel means stores a length of flexible hollow cable and is operable when rotated to advance the free end of the cable into the metallic discharge line. Conductors extending through the cable provide for electrically connecting an audio frequency signal generator located on the reel means to a transmitter antenna attached to the free end of the cable. A directional receiver means determines the location of the discharge line by detecting the high strength, varying frequency signals generated by the audio frequency signal generator and radiated by the transmitter antenna through the walls of the metallic discharge line.

Discharge pipe line locator

A plurality of light sensitive cells are positioned on a target face for receiving a moving beam of light from a light beam generator. The generator develops a datum plane of light. The cells are operatively associated with an electric circuitry connected to lights for translating visually whether the target is high, centered or low relative to the plane of light generated by the oscillating laser beam. The cells include portions offset from the other to permit independent or simultaneous interception thereof by the plane of light. The target by means of the light beam designates or depicts its position with respect to the plane of light intercepting the target either intermediate each cell, or on one or more of said cells. The target face is rotatable about an axis to adjust the positions of the cells relative to the plane of projected light thus providing a means for varying the high, centered or low reading produced by the target.

Light target and sensor

A method and apparatus for generating an output signal selectively displaced in phase from an input signal wherein the phase displacement remains the same irrespective of changes in the input signal frequency. A reference signal related in amplitude to the frequency of the input signal and a comparing signal which varies at a predetermined rate for a period of time related to the frequency of the input signal are compared, and a pulse is generated in response to the comparison. More specifically, a capacitor is charged and discharged from alternately enabled positive and negative constant current sources during successive interpulse periods of the input signal. The voltage on the capacitor is stored at the end of each charging period and the varying voltage across the capacitor is compared with one or more percentages of the stored voltage to generate output pulses. The output pulses may be combined with the input signal to provide frequency multiplication or the percentage may be made variable to provide variable phase shifting. A system for increasing the resolution of measurements obtained from a digital transducer and a system for generating selectively phase shifted control signals are also disclosed.

Variable frequency multiplier and phase shifter

A driver circuit for a tone generator that is adapted to cause the tone generator to produce a pleasant sounding chime. The circuit comprises high and low frequency oscillator circuits whose decaying sawtooth type outputs are summed and modulated to produce the desired chime effect.

Driver circuit for tone generator

A system for repetitively providing a series of pulses of linearly varying periodicity where first and second signals are provided which advance at respective different constant rates and which are fed to a comparator. When the values of the two signals match, the signal having the faster rate of advance is reset so that the comparator provides output pulses of linearly varying periodicity. In an analog embodiment of the invention, the first and second signals are provided by voltage ramp generators connected to an analog comparator which resets that generator whose ramp has the steeper slope in response to each match. In a digital embodiment of the invention, the first and second signals are provided as the contents of a pair of counters which are advanced at different rates and whose contents are connected to a digital comparator. Each time the contents of the two counters match, that counter advanced at the faster rate is reset so that the output of the digital comparator is repetitive series of pulses occurring at a correspondingly linearly varying periodicity until either the slower counter resets itself or is reset by other means and then the cycle repeats. In a modification of this embodiment, a third counter is provided which is advanced at the same rate as the faster counter but which is reset each time a second digital comparator ascertains that the normal bit contents of this third counter match the first (n-1) bits and n, the complement of the last bit of the counter advanced at the slower rate until the slower counter is reset and the cycle repeats. In this modified digital embodiment, the two comparators repetitively provide two series of pulses, each of a linearly varying periodicity, but which are timeshifted by half a slower counter cycle with each other.

Gerard R Patrick

Papers

Signal rate converter