Neuromuscular stimulator

Claim 1

A muscle stimulator comprising, in combination: oscillator means for producing a periodic output signal at a predetermined repetition rate; rate control means coupled to said oscillator means for altering the repetition rate of said oscillator means; inverter means, coupled to receive the output of said oscillator means, for producing a periodic output signal having a polarity opposite to that of the periodic output signal produced by said oscillator means; treatment timer means for generating a first logic signal after a predetermined treatment time interval; treatment timer control means coupled to said treatment timer means for establishing the predetermined treatment time of said treatment timer means; cycler means for repetitively producing a second logic signal which remains at a first logic level for a predetermined "on" time interval and a second logic level for a predetermined "off" time interval; first cycler control means completed to said cycler means for setting the predetermined "on" time interval of said cycler means; second cycler control means coupled to said cycler means for setting the predetermined "off" time interval of said cycler means; external switch means; plug means operatively connected to said external switch means; accessory jack means constructed and arranged for receiving said plug means and for providing a third logic signal when said plug means is inserted in said jack means and said external switch means is in a particular condition or when said plug is not inserted in said jack; momentary contact switch means for producing a fourth logic signal when said momentary .[.on.]. .Iadd.contact .Iaddend.switch means is actuated; first and second ramp generator circuit means connected to receive said first, second, third and fourth logic signals and for producing first and second output ramp signals changing from a first to a second level at first and second predetermined rates, subsequent to receipt of either of said first, second, third or fourth logic signals; first and second ramp generator control means coupled respectively to said first and second ramp generator circuit means for independently altering the rate of change of the output ramp signals of said first and second ramp generator circuit means; first pulse width circuit means coupled to receive the ramp signal from said first ramp generator circuit means and to receive the periodic output signal from said oscillator means and for producing a fixed amplitude pulse signal having a pulse width increasing at a rate proportional to the rate of change of the ramp signal from said first ramp generator circuit means at the predetermined repetition rate of said oscillator means until the output signal of said .[.second.]. .Iadd.first .Iaddend.ramp generator circuit means reaches the second level and the pulse width of the pulse signal reaches a predetermined pulse width; second pulse width circuit means coupled to receive the ramp signal from said second ramp generator circuit means and to receive the inverted periodic output signal of said inverter means and for producing a fixed amplitude pulse signal having a pulse width increasing at the rate of change of said ramp from said second ramp generator circuit means at the predetermined repetition rate of said oscillator means until the output signal of said second ramp generator circuit means reaches the second level and the pulse width of the pulse signal reaches a predetermined pulse width; first and second output circuit means connected to receive the pulse outputs of said first and second pulse width circuit means respectively and for producing a balanced biphasic constant current output signal; and first and second output circuit control means for adjusting the current amplitude of the output pulses of said first and second output circuits respectively.