Envelope tracking method, system, and device employing the method

An envelope tracking system comprises:

• a first envelope tracking device and a second envelope tracking device, wherein the first envelope tracking device and the second envelope tracking device comprise a fine slot peak tracking circuit, an envelope modulate, and at least one power amplifier;
• the fine slot peak tracking circuit configured to:
• generate sample signals by sampling input signals coupled to the fine slot peak tracking circuit;
• calculate square of the amplitude of the sample signals;
• divide the sample signals into equal parts based on a pulse width, and extract the maximum number of equal parts of the calculated sample signals;
• generate envelope signals based on a square root of the maximum number of equal parts of the calculated sample signals;
• add an offset to the envelope signals;
• expand the added envelope signals;
• and
• smooth the expanded envelope signals;
• the fine slot peak tracking circuit is electrically connected to the at least one power amplifier through the envelope modulator;
• the envelope modulator configured to generate envelope voltage signals according to the smoothed envelope signals, and transmit the envelope voltage signals to a drain of the at least one power amplifier, and the envelope voltage signals are time-aligned with amplified signals transmitted to a gate of the at least one power amplifier;
• couple signals transmit by antenna of the first envelope tracking device to antenna of the second envelope tracking device, and the second envelope tracking device generates pre-distortion signals by feeding back the signals to a digital pre-distortion circuit of the first envelope tracking device;
• and
• couple signals transmit by the antenna of the second envelope tracking device to the antenna of the first envelope tracking device, and the first envelope tracking device generates pre-distortion signals by feeding back the signals to a digital pre-distortion circuit of the second envelope tracking device.

An envelope tracking method applied in an envelope tracking device, the envelope tracking device comprises a fine slot peak tracking circuit, at least one power amplifier, and an envelope modulator,

• the method comprises:
• generating sample signals by sampling input signals coupled to the fine slot peak tracking circuit;
• calculating square of the amplitude of the sample signals;
• dividing the sample signals into equal parts which are based on a pulse width, and extracting the maximum of equal parts of the calculated sample signals;
• generating envelope signals based on a square root of the maximum of equal parts of the calculated sample signals.