Miller-encoded message decoder

Claim 1

Apparatus for decoding a Miller-encoded signal in the form of binary data at a clock frequency F, which comprises: a transition detector, receiving said Miller-encoded signal, for detecting the transitions in said signal; a phase controllable local clock, having a control signal input, for generating a clock signal Hr at the rate F, said clock signal comprising a train of bidirectional pulses providing first and second levels each of duration 1/2F; means, connected to the output of said transition detector and to the output of said clock circuit, for generating a pulse I of duration 1/2F subsequent to each transition in the signal to be decoded when clock signal Hr is at a predetermined one of said first and second levels, said pulses I constituting an output signal S, means for generating a control signal for said local clock from said clock signal Hr and said signal S, said local clock control signal generating means comprising means, connected to the output of said pulse-generating means and to the output of said clock circuit, for phase modulating said signal Hr by said signal S, and a low-pass filter connected to the output of said phase modulating means, the output signal of said low-pass filter being applied to the control signal input of said local clock so that the pulses of signal Hr providing said predetermined level are centered on the Miller-encoded signal transitions which produced pulses I, the original binary data being restored by sampling signal S with edges of signal Hr which go from said predetermined level to the other.