Regenerator/synchronizer method and apparatus for missing-clock timing messages
OwnerStephen L. Knappinventor
Life of this patent
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Abstract
In a bit-serial type data transmission system using the interruption of clock pulses in the timing message to identify separate data word groups in the data messages, a method and apparatus for recovering the transmitter clock oscillator frequency and thereby identifying the interruption interval. The method and apparatus in addition provide signals which may be employed to control the reception of the serial data word groups, to indicate the availability of the data groups as bit-parallel words, and to provide for the retransmission of the received data word groups or the transmission of other word groups.
Claims18
In a system using a transmission channel means for carrying sequential timing messages from a transmitting station to a receiving station, wherein said timing messages each consist of an interval containing N cycles of a clock, each of said cycles of a clock being of duration equal to k cycles of an oscillator associated with the transmitting station, and an interval without clock, said interval without clocks being of duration equal to m cycles of said oscillator associated with the transmitting station, where N, k, and m are positive integers, a timing recovery apparatus connected to said transmission channel means and comprising:
- a phase-frequency detector circuit;
- a variable oscillator with at least one frequency control input;
- a modulo N divider circuit, with input connected to said transmission channel means and with output connected to one input of said phase-frequency detector circuit;
- a modulo (kN+m) divider circuit, with input connected to the output of said variable oscillator and with output connected to another input of said phase-frequency detector circuit;
- the output of said phase-frequency detector circuit being connected to the frequency control input of said variable oscillator so as to cause said variable oscillator to operate at the frequency of said oscillator associated with the transmitting station.
A timing recovery method for use in a system using a transmission channel means for carrying sequential timing messages from a transmitting station to a receiving station, wherein each timing message consists of:
- an interval containing N cycles of a clock, each of said cycles of a clock being of duration equal to k cycles of an oscillator associated with the transmitting station, N and k being positive integers;
- and an interval without clocks, said interval without clocks being of duration equal to m cycles of said oscillator associated with the transmitting station, m being a positive integer;
- said timing recovery method comprising the steps of:
- providing a phase-frequency detector circuit;
- providing a variable oscillator with at least one frequency control input;
- providing a modulo N divider circuit, with input connected to said transmission channel means and with output connected to one input of said phase-frequency detector circuit;
- providing a modulo (kN+m) divider circuit, with input connected to the output of said variable oscillator and with output connected to another input of said phase-frequency detector circuit;
- and connecting the output of said phase-frequency detector circuit to the frequency control input of said variable oscillator so as to cause said variable oscillator to operate at the frequency of said oscillator associated with the transmitting station.
Dependencies are inferred from the claim text.