Tunable phase shift oscillator with variable rc filter

Claim 1

A TUNABLE OSCILLATOR INCLUDING: TRANSISTOR AMPLIFYING MEANS HAVING INPUT AND OUTPUT TERMINALS; A PHASE SHIFT FILTER DEVICE IN A MONOLITHIC STRUCTURE HAVING A DISTRIBUTED RESISTANCE CONNECTED BETWEEN SAID INPUT AND OUTPUT TERMINALS, A DISTRIBUTED CAPACITANCE OPERATIVE WITH SAID DISTRIBUTED RESISTANCE TO FORM A RESISTIVE-CAPACITIVE NETWORK, AND A LUMPED RESISTOR OPERATIVELY CONNECTED TO SAID DISTRIBUTED CAPACITANCE, WITH THE FEEDBACK CHARACTERISTICS OF SAID PHASE SHIFT DEVICE BEING DEPENDENT ON THE BIAS VOLTAGE APPLIED THERETO; CAPACITOR MEANS CONNECTED BETWEEN SAID LUMPED RESISTANCE AND GROUND AND MEANS CONNECTED IN PARALLEL WITH SAID CAPACITOR MEANS FOR APPLYING A VARIABLE D.C. BIAS VOLTAGE BETWEEN SAID LUMPED RESISTANCE AND GROUND, WHEREBY A REVERSE D.C. BIAS MAY BE APPLIED TO CHANGE THE TUNING OF THE OSCILLATOR WHILE THE VALUE OF THE LUMPED RESISTANCE TO A.C. GROUND AND THE FEEDBACK CHARACTERISTICS REMAIN SUBSTANTIALLY UNCHANGED.