Unipolar to bipolar converter

Abstract

A unipolar to bipolar converter includes a source of unipolar data pulses and of noise pulses. Each data pulse has a pulse width in excess of a time duration t. Each noise pulse has a pulse width less than the time duration t. A one-shot multivibrator, with an input coupled to the source, normally provides a first output signal indicative of one binary state. The multivibrator switches to a second binary output state for the time duration t when the multivibrator receives the leading edge of one of the pulses (data or noise). A flip-flop, coupled to receive the output signals of the one-shot multi-vibrator, and further adapted to receive the source pulses, provides a first output signal at one fixed binary state upon the simultaneous presence of one of the source pulses and the first output signal from the one-shot multivibrator. Otherwise, the flip-flop provides a second output signal at the opposite fixed binary state. A second one-shot multivibrator, coupled to receive the output signals from the first flip-flop, normally provides a first output signal indicative of one binary state. The second one-shot multivibrator switches to a second output signal indicative of the other binary state for a time duration t.sub.1 (which is not necessarily the same as the time duration t) when it receives the trailing edge of the first output signal from the first flip-flop. A second flip-flop coupled to receive the output signals from the second one-shot multivibrator, provides alternate output signals indicative of the two binary states. The second flip-flop switches state upon receipt of the trailing edge of the second one-shot multivibrator second output signal. The second flip-flop and the source pulses control means for providing an output signal which corresponds to the alternate switching of the polarity of the source pulses, dependent upon the state of the second flip-flop alternate output signals.