Power control loop, transmitter with the power control loop and method for controlling output power of a transmitter device
View Patent ↗A power control loop includes a low-frequency signal path and a high-frequency signal path with the delay compensation block. The delay compensation block is used to determine a correlation between an average reference level and an average measured power level. The result may control a delay line to compensate a time misalignment in the power control loop.
1. A power control loop, comprising:
a low frequency signal path configured to receive a first signal indicating a measured power level and a second signal indicating a reference power level;
a high frequency signal path configured to receive the first signal and the second signal, the high frequency signal path comprising a compensation block configured to provide an adjustment signal for delaying the second signal to form a delayed second signal in response to signal components of the first and second signal, for use to generate a power control signal; and
a control device configured to provide the power control signal in response to a difference between the measured power level of the first signal and the reference power level of the delayed second signal.
2. The power control loop of claim 1 , wherein the measured power level comprises an envelope of a measured signal and the reference power comprises an envelope of a reference signal.
3. The power control loop of claim 1 , wherein the compensation block comprises at least one zero crossing detector configured to detect a zero crossing of the signal components.
4. The power control loop of claim 3 , wherein the zero crossing detector comprises a saturation amplifier configured to provide pulsed signals in response to the signal components.
5. The power control loop of claim 1 , wherein the compensation block comprises a delay locked loop configured to provide the adjustment signal.
6. The power control loop of claim 1 , wherein the high frequency signal path comprises a first high-pass or band-pass filter configured to receive and filter the first signal and a second high-pass or band-pass filter configured to receive and filter the second signal.
7. The power control loop of claim 1 , wherein the compensation block comprises a logical operator device coupled with its inputs to respective zero crossing detectors.
8. The power control loop of claim 1 , wherein the compensation block comprises a delay circuit configured to delay the signal components of the first signal in response to the adjustment signal.
9. The power control loop of claim 1 , wherein the low frequency signal path comprises a first low-pass filter configured to receive and filter the first signal and a second low-pass filter configured to receive and filter the second signal.
10. The power control loop of claim 9 , wherein a delay circuit with an adjustable delay is coupled to an output of the second low-pass filter, the delay circuit comprising a control input configured to receive the adjustment signal.
11. The power control loop of claim 1 , wherein the low frequency signal path comprises a delay circuit with an adjustable delay configured to delay the signal portion of the second signal in response to the adjustment signal.
12. The power control loop of claim 1 , wherein the low frequency signal path comprises a multiplier circuit to scale the second signal with a reference scaling factor.
13. The power control loop of claim 1 , wherein the compensation block comprises a circuit configured to determine a temporal correlation between the signal components of the first and the second signal.
14. The power control loop of claim 1 , wherein the low frequency signal path and the high frequency signal path are adapted to each receive digital first and digital second signals.
15. The power control loop of claim 1 , wherein the first signal indicates a measured envelope power level.
16. The power control loop of claim 1 , wherein the compensation block is configured to determine a deviation of a timing between the first signal and the second signal, and wherein the adjustment signal is a function of the timing deviation.