Modulator and signaling method
Phase shift key modulators ( 100, 500, 1000, 1400, 1700 ) are provided in which a multiphase signal source ( 108, 1402, 1406 - 1412,1702 ) is used to generate a plurality of phases of a carrier signal. A selector ( 110 ) is used to select one phase or a sequence of phases of the carrier signal to represent each bit pattern that is received from a binary data source ( 102, 1422 ). The multiphase signal source preferably comprises a multiphase oscillator that includes a phase locked ring of variable propagation delay inverters ( 202 ). Preferably, a phase sequencer ( 502 ) is used to select a monotonic sequence of phases to represent each bit pattern. Preferably two phase selectors ( 110, 1004 ) are used to simultaneously select two phases of carrier signal, and a phase interpolator ( 1106 ) is used to generate a sequence of phases from the two phases selected by the two phase selectors ( 110, 1004 ).
1. A modulator comprising: a multi phase signal source including: a plurality of signal source outputs for outputting a plurality of phases of a carrier signal; a first phase selector including: a plurality of signal inputs coupled to the plurality of signal source outputs of the multi phase signal source; a first selector output for selectively outputting a first sequence of selected phases of the carrier signal; a second phase selector including: a plurality of signal inputs coupled to the plurality of signal source outputs of the multi phase signal source; a second selector output for selectively outputting a second sequence of selected phases of the carrier signal; a summer including: a first input coupled to the first selector output; a second input coupled to the second selector output; an output for outputting, in response to a signal received from the first selector and a signal concurrently received from the second selector, at least one weighted sum of the signal received from the first selector and the signal received from the second selector.
2. The modulator according to claim 1 further comprising: a binary data source including: one or more binary data outputs for supplying binary data; a delay including: one or more inputs coupled to at least a subset of the one or more binary data outputs of the binary data source; and one or more of outputs for outputting delayed binary data; and wherein: the first phase selector further comprises: one or more phase select inputs coupled to at least a subset of the one or more binary data outputs of the binary data source; and the second selector further comprises one or more phase select inputs coupled to at least a subset of the one or more outputs of the delay.
3. A method of producing phase modulated signals, the method comprising the steps of:
producing a plurality of discrete phases of a carrier signal;
inputting a first binary data signal that is characterized by a signal state period; inputting a second binary data signal that is characterized by the signal state period and is offset in time from the first binary data signal by about one-half of the signal state period; and
coupling a sequence of discrete phases that includes two or more of the plurality of discrete phases of the carrier signal to an output in response to each concurrent set of states of the one or more binary data signals, comprising for each one-half signal state period outputting a monotonic sequence of discrete phases at a rate of about one quadrant per one-half signal state period;
at intervals of one-half the signal state period, at each potential signal state transition of the first and second binary data signal: in the case that a signal state transition occurs maintaining a phase direction that characterizes selections of successive phases; and in that case that a signal state transition does not occur reversing the phase direction that characterizes selections of successive phases.
4. The method according to claim 3 wherein phases are output of a rate of at least about eight phases per signal state period.
5. A modulator comprising:
a multi phase signal source including a plurality of signal source outputs for outputting a plurality of phases of a carrier signal;
a selector including:
a plurality of selector inputs coupled to the plurality of signal source outputs for receiving the plurality of phases of the carrier signal;
an output for selectively outputting a selected phase of the carrier signal; and
one or more select inputs for receiving binary data for specifying the selected phase; and
a binary data source coupled to the one or more select inputs for supplying the binary data, wherein the binary data source comprises: an I and Q channel binary sequence source including: a first channel output coupled to a first select input of the one or more select inputs; and a second channel output coupled to a second select input of the one or more select inputs, wherein: the binary data is supplied at a predetermined rate that is characterized by a signal state period; and the binary data source further comprises a one half signal state period delay intervening between the first channel output and the first select input.