CABLE FINDER Russian patent published in 1998 - IPC

FIELD: radio engineering, commutators. SUBSTANCE: device has receiving magnetic antenna, narrow-band selective amplifier, detector, oscillator, pointer-type instrument, acoustic device. First narrow-band filter is connected to input of first amplification stage of direct amplifier. Gain control regulator is inserted between first and second amplification stages, second narrow-band filter is connected between second and third amplification stages, output of third amplification stage is connected to peak detector which output is connected through resistor to collector of transistor which emitter is connected to general point of circuit. Its base is connected through parallel circuit of resistor and capacitor to output of operational amplifier (transistor) which implements oscillator, which working frequency differs from working frequency of first and second narrow-band filters. Collector of said transistor is also connected through isolating capacitor to high-resistance input of amplifier which output is connected to acoustic device. Device provides possibility to detect depth of cable location using rotation of magnetic antenna in horizontal plane by angle of 63.435 degrees. EFFECT: increased sensitivity, increased stability to noise, decreased weight (by factor of 4), simplified search method and cable depth detection. 2 cl, 2 dwg