Electronic potentiometer

An adjuster for providing a potentiometric type of adjustment, comprising:

• a control generator for providing a bidirectionally adjustable digital signal, the direction of adjustment of said digital signal being immediately reversible, said control generator having means for producing from and in response to said digital signal an adjusting signal which is analog and bidirectionally adjustable;
• drive means coupled to said control generator for providing a drive signal in response to said adjusting signal;
• and
• a transducer means having an input coupled to said drive means and an output electrically isolated from said input, said output of said transducer means being operable to conduct by a variable amount in response to said adjusting signal to simulate potentiometric action, said control generator further comprising:
• (a) clock means for providing timing pulses;
• (b) gate means coupled to said clock means for gating said timing pulses;
• and
• (c) counter means coupled to said gate means for accumulating a count in response to timing pulses gated by said gate means and for providing a count signal signifying said count, said counter means being operable to count bidirectionally and wherein said gate means is operable to direct said timing pulses to cause counting in either direction in said counting means;
• (d) presetting means coupled to said counter means for presetting it to a predetermined intermediate count;
• and
• (e) limit means coupled around said counting means for stopping it from counting beyond a predetermined limit.

A control generator for providing a variable count signal for controlling the input to a radio frequency power circuit, comprising:

• clock means for providing timing pulses;
• gate means coupled to said clock means for gating said timing pulses;
• counter means coupled to said gate means for accumulating a count in response to timing pulses gated by said gate means and for providing a count signal signifying said count, said counter means being operable to count bidirectionally, said gate means being operable to direct said timing pulses to cause immediately reversible counting in either direction in said counting means;
• converter means coupled to said counter means for providing an analog signal proportional to the count of said counter means;
• a radio frequency power circuit having a control input connected to the output of said converter means, said circuit being operable to produce a radio frequency signal having a magnitude varying in response to the count of said counter means.