Delay adjustment
There is disclosed an envelope tracking amplification stage comprising an input path and an envelope path and a delay stage in one of the input path and the envelope path, the delay of the delay stage being determined in dependence on the slope polarity of a signal representing the input and whether the signal in the input path leads or lags the signal in the envelope path.
1. An envelope tracking amplification stage comprising:
an input path;
an envelope path; and
a delay stage in one of the input path and the envelope path, a delay of the delay stage being determined in dependence on a slope polarity of a signal representing an input signal and whether a signal in the input path leads or lags a signal in the envelope path.
2. The envelope tracking amplification stage of claim 1 , wherein the slope polarity of the signal representing the input signal is determined by determining a slope polarity of any one of the signals in the input path, the envelope path, or an output path.
3. The envelope tracking amplification stage of claim 2 , wherein the slope polarity of the signal representing the input signal is determined in dependence on a portion of the input signal which is not a minima or a maxima of the input signal.
4. The envelope tracking amplification stage of claim 1 , wherein determining whether the signal in the input path leads or lags the signal in the envelope path comprises:
comparing an instantaneous signal amplitude of the signal representing the input signal to an average signal amplitude of the signal representing the input signal.
5. The envelope tracking amplification stage of claim 4 , wherein the average signal amplitude is determined in dependence on the slope polarity.
6. The envelope tracking amplification stage of claim 1 , wherein determining whether the signal in the input path leads or lags the signal in the envelope path comprises:
comparing an instantaneous signal gain of the signal representing the input signal to an average signal gain of the signal representing the input signal.
7. The envelope tracking amplification stage of claim 6 , wherein the average signal gain is determined in dependence on the slope polarity.
8. A method for determining a delay in an input path or an envelope path of an envelope tracking amplification stage, the method comprising:
determining a slope polarity of a signal representing an input signal;
determining whether a signal in the input path leads or lags a signal in the envelope path, wherein the signal in the input path is based on the input signal; and
determining the delay based on the slope polarity and whether the signal in the input path leads or lags the signal in the envelope path.
9. The method of claim 8 , wherein determining the slope polarity of the signal representing the input signal comprises:
determining the slope polarity of any one of the signals in the input path, the envelope path, or an output path.
10. The method of claim 9 , wherein determining the slope polarity of the signal representing the input signal is based on a portion of the input signal which is not a minima or a maxima of the input signal.
11. The method of claim 8 , wherein determining whether the signal in the input path leads or lags the signal in the envelope path comprises:
comparing an instantaneous signal amplitude of the signal representing the input signal to an average signal amplitude of the signal representing the input signal.
12. The method of claim 11 , wherein the average signal amplitude is determined in dependence on the slope polarity.
13. The method of claim 8 , wherein determining whether the signal in the input path leads or lags the signal in the envelope path comprises:
comparing an instantaneous signal gain of the signal representing the input signal to an average signal gain of the signal representing the input signal.
14. The method of claim 13 , wherein the average signal gain is determined in dependence on the slope polarity.