Phase digitizer for radio communications
AssigneeEricsson Inc.
InventorPeter Bo Holmqvist
Life of this patent
Estimating the term…
Abstract
A phase digitizer and method with error compensation is provided that utilizes recordings from a digitally generated phase reference to measure the relative time between events, such as, for example, between the input zero crossing and sample pulse events. The digital reference has a constant frequency which is equal to the desired signal frequency, and thus the phase of the reference can be used to measure the time between events. Consequently, by using the existing digitally generated phase reference, the hardware "costs" associated with implementing the prior phase digitizer error compensation approaches can be significantly reduced and/or eliminated.
Claims27
A method of digitizing the phase of an input signal, said method comprising the steps of:
- generating a phase reference signal having a frequency substantially equal to a desired frequency of the input signal;
- computing a value representative of the phase of the input signal at a time when a sampling signal occurs, said computing step comprising the steps of:
- recording a first value (rs) of the phase reference signal in response to the occurrence of the sampling signal, and a second (r1) and third (r2) values of the phase reference signal in response to a first and a second zero crossing of the input signal respectively, the first and second zero crossings being nearest in time to the occurrence of the sampling signal;
- computing a ratio comprising the first value relative to the values of said second and said third values of the phase reference signal;
- and
- computing said value representative of the phase of the input signal responsive to said ratio.
An apparatus for digitizing the phase of an input signal, said apparatus comprising:
- means for generating a phase reference signal having a frequency substantially equal to a desired frequency of the input signal;
- and
- means for computing a value representative of the phase of the input signal at a time when a sampling signal occurs, said means for computing further comprising:
- means for recording a first value (rs) of the phase reference signal in response to the occurrence of the sampling signal, and a second (r1) and third (r2) value of the phase reference signal in response to a first and a second zero crossing of the input signal respectively, the first and second zero crossings being nearest in time to the occurrence of the sampling signal;
- means for computing a ratio comprising the first value relative to the values of said second and said third values of the phase reference signal;
- and
- means for computing said value representative of the phase of the input signal responsive to said ratio.
An apparatus for digitizing the phase of an input signal, said apparatus comprising:
- a reference generator providing as an output a phase reference signal having a frequency substantially equal to a desired frequency of the input signal;
- and
- a computational unit receiving values of the phase reference signal at a first and a second zero crossing of the input signal and at an occurrence of a sampling pulse, said computational unit providing as an output a value representing the digitized phase of the input signal at the occurrence of the sampling pulse, and wherein said computational unit further comprises a register coupled to the phase reference output of said reference generator, wherein said register stores a first value (rs)of the phase reference signal in response to the occurrence of the sampling signal, and a second (r1) and third (r2) value of the phase reference signal in response to the first and second zero crossings of the input signal, and wherein the first and second zero crossings are nearest in time to the occurrence of the sampling signal, said computational unit further computing a ratio comprising said first value relative to the values of said second and said third values of the phase reference signal, a value representative of the phase of the input signal responsive to said ratio being further computed by said computational unit.
Dependencies are inferred from the claim text.