Manchester decoder using gated delay line oscillator
AssigneeUnisys Corporation
InventorsThomas G. Palkert, John A. Kolling
Life of this patent
Estimating the term…
Abstract
Manchester level coded data is converted to NRZ by two gated delay line oscillators responsive to differential Manchester signals for providing a single gated pulse in response to consecutive data cells conveying the same data and for providing two pulses in response to a data change. A decoder circuit responds to the two pulse condition by toggling a data flip-flop that provides the NRZ data. The flip-flop also controls gates responsive to the two oscillators for selecting between the two oscillator signals to provide the NRZ clock. When the system bus ceases data transmission, three or more oscillator pulses are generated, the detection of which is utilized to preset the data flip-flop.
Claims8
Apparatus for converting Manchester coded data signals into non-return to zero data signals, said Manchester coded data signals having first and second components that are the inverse of each other, said Manchester coded data signals being formatted in consecutive data cells, comprising
- a first gated oscillator enabled and disabled by first and second states, respectively, of said first component for generating a single pulse between enablement and disablement in response to consecutive data cells conveying the same binary data and for generating two pulses between enablement and disablement in response to consecutive data cells conveying a change in binary data,
- a second gated oscillator enabled and disabled by first and second states, respectively, of said second component for generating a single pulse between enablement and disablement in response to consecutive data cells conveying the same binary data and for generating two pulses between enablement and disablement in response to consecutive data cells conveying a change in binary data,
- first logic means responsive to said Manchester coded data signals and coupled to said first gated oscillator for providing a first toggling signal in response to the occurrence of said two pulses from said first gated oscillator, said first logic means being reset by said Manchester coded data signals,
- second logic means responsive to said Manchester coded data signals and coupled to said second gated oscillator for providing a second toggling signal in response to the occurrence of said two pulses from said second gated oscillator, said second logic means being reset by said Manchester coded data signals, and
- bistable means responsive to said first and second toggling signals for toggling in response to the occurence of either said first or second toggling signal,
- said bistable means providing said non-return to zero data signals.
Dependencies are inferred from the claim text.