Patent ID: 6172634
Filing Date: 2001-01-09
Classification: H03M

Abstract:
A line driver, comprising:an input for receiving a Manchester-encoded digital data signal, the data signal comprising a series of positive and negative pulse levels representing digital HI and LO, respectively;a wave-shaping circuit for converting the digital data signal into an analog signal, the wave-shaping circuit comprising:a bank of n current sources c.sub.0 -c.sub.n-1 with a combined output, each current source being scaled by a coefficient,each current source having switches controlled by a switching signal input cnt.sub.0 -cnt.sub.n-1 for actuating the current sources in a selected sequence during each input data pulse, thereby generating as a combined output a staircase pulse signal with n steps for each input data pulse,wherein, when the Manchester-encoded input represents a binary sequence of all-ones or all-zeros data, the levels a.sub.k of the staircase pulse signal output approximate a sinusoidal curve ##EQU7##where k=0 to n-1, and where ##EQU8##is the fundamental frequency of the input signal,wherein the coefficients b.sub.k used to scale the current sources are defined from the maximum peak value of the signal: ##EQU9##where k=0 to n-1,wherein current sources c.sub.k are scaled as follows: ##EQU10##for k=0 to n-1, andwherein n=8 and wherein current sources c.sub.0 -c.sub.7 are actuated sequentially in pairs starting from a positive or negative peak level of the input data, with pairs (c.sub.0, c.sub.7), (c.sub.1, c.sub.6), (c.sub.2, c.sub.5), and (c.sub.3, c.sub.4) being turned off sequentially in order followed by pairs (c.sub.3, c.sub.4), (c.sub.2, c.sub.5), (c.sub.1, c.sub.6), and (c.sub.0, c.sub.7) being turned on sequentially in order.