Apparatus and method for conditioning a modulated signal in a communications device
View Patent ↗A device for transmitting information in a communications signal is envisioned. The information is modulated, at least in part, with a first angle-related characteristic. The device has a digital conversion circuit operable to convert information to be broadcast into a digital form. A constellation mapper is coupled to the digital conversion circuit, and is operable to convert the digital information into information associated with a constellation. A trajectory generation circuit generates samples denoting a trajectory within the constellation for the information. A transition analysis circuit determines a change in value of an angle-related characteristic in a transition between two samples, and a threshold detection circuit detects whether the change in value fails to meet a particular threshold. An angle-related characteristic distribution circuit can then distribute a portion of the change in value associated with the transition to at least one other transition.
1. An apparatus for transmitting information in a communications signal, the information modulated, at least in part, with an angle-related characteristic, the apparatus comprising:
a digital conversion circuit for converting information to be broadcast into a digital form;
a constellation mapper, following the digital conversion circuit, for converting the digital information into information associated with a constellation;
a trajectory generation circuit, following the constellation mapper, for generating samples denoting a trajectory within the constellation;
a transition analysis circuit, following the trajectory generation circuit, for determining a change in value of the angle-related characteristic in a transition between two samples;
a threshold detection circuit, following the transition analysis circuit, for detecting whether the change in value of the angle-related characteristic fails to meet a particular clip threshold; and
an angle-related characteristic distribution circuit, following the threshold detection circuit, for determining a clip amount by which the change in value of the angle-related characteristic surpasses the clip threshold, and for distributing the clip amount to at least one other transition so that an amount of distribution matches the clip amount; and
a radio frequency generator following the angle-related characteristic distribution circuit, the radio frequency generator generating a radio frequency signal depending upon an output signal of the angle-related characteristic distribution circuit,
wherein the particular clip threshold is decided according to: the capability of the radio frequency generator to changing angle-related characteristic; and a spectral content of the angle-related characteristic.
2. The apparatus of claim 1 wherein the constellation has one domain associated with the angle-related characteristic.
3. The apparatus of claim 1 wherein the angle-related characteristic is frequency.
4. The apparatus of claim 1 wherein the angle-related characteristic is phase.
5. The apparatus of claim 1 wherein the communications signal is a time-varying amplitude signal.
6. The apparatus of claim 1 wherein the clip amount is distributed to a preceding transition and a succeeding transition.
7. The apparatus of claim 1 wherein the clip amount is distributed to at least one temporally preceding transition.
8. The apparatus of claim 1 wherein the clip amount is distributed to at least one temporally succeeding transition.
9. A method for transmitting information in a communications signal, the information modulated, at least in part, with an angle-related characteristic, the method comprising the steps of:
converting information to be broadcast into a digital form by using a digital conversion circuit;
converting the digital information into information associated with a constellation;
generating samples denoting a trajectory within the constellation by using a trajectory generation circuit;
determining a change in value of the angle-related characteristic in a transition between two samples;
detecting whether the change in value of the angle-related characteristic fails to meet a particular clip threshold;
determining a clip amount by which the change in value of the angle-related characteristic surpasses the clip threshold;
distributing the clip amount to at least one other transition by using a distribution circuit so that an amount of distribution matches the clip amount; and
generating a radio frequency signal depending upon values of the angle-related characteristic after the distribution by using a radio frequency generator,
wherein the particular clip threshold is decided according to: the capability of the radio frequency generator to changing angle-related characteristic; and a spectral content of the angle-related characteristic.
10. The method of claim 9 wherein the constellation has one domain associated with the angle-related characteristic.
11. The method of claim 9 wherein the angle-related characteristic is frequency.
12. The method of claim 9 wherein the angle-related characteristic is phase.
13. The method of claim 9 wherein the communications signal is a time-varying amplitude signal.
14. The method of claim 9 wherein the clip amount is distributed to a preceding transition and a succeeding transition.
15. The method of claim 9 wherein the clip amount is distributed to at least one temporally preceding transition.
16. The method of claim 9 wherein the clip amount is distributed to at least one temporally succeeding transition.