Method and system for transmitter envelope delay calibration

A delay adjustment system for use in an RF transmitter having an envelope path and an RF path, wherein the RF transmitter has a receiving end for receiving 1-baseband data and Q-baseband data and providing a first signal and a second signal based on the received data, and wherein the first signal is conveyed to the RF path so as to obtain a phase modulated RF signal indicative of the first signal at an end of the RF path and the second signal is conveyed to the envelope path so as to obtain an envelope signal indicative of the second signal at an end of the envelope path, the phase modulated RF signal provided to an input of output amplifier for transmission, the envelope signal provided to a voltage supply of the output amplifier, said adjustment system comprising:

• a switching module disposed between the receiving end and the output amplifier;
• a test signal generator for providing a first test signal and a second test signal to the switching module, the first and second test signals having a periodic waveform, the switching module operable in a first state and in a second state, such that
• when the switching module is operated in the first state, the first test signal is conveyed to the RF path for providing a first further signal indicative of the first test signal to the end of the RF path, and the second test signal is conveyed to the envelope path for providing a second further signal indicative of the second test signal to the end of the envelope path, and
• when the switching module is operated in the second state, the first test signal is disconnected from the RF path and the second signal is disconnected from the envelope path;
• a phase modulator operatively connected to the end of the RF path and the end of the envelope path for obtaining the first and second further signals when the switching module is operated in the first state,
• means, responsive to at least the obtained first further signal, for providing a demodulated waveform signal having a peak-to-peak amplitude;
• and
• an adjustable delay device, disposed in one of the RF path and the envelope path, for minimizing the peak-to-peak amplitude.

An RF transceiver front end comprising:

• a transmitter for receiving I-baseband data and Q-baseband data into an RF signal for transmission, and
• a receiver having an IQ demodulator for converting received RF signals into I-signal and Q-signal, wherein the transmitter comprises:
• a power amplifier having an input end, a voltage supply terminal and an output end, the output end connected to a transmit path for transmitting the RF signal;
• a data receiving end for receiving the I-baseband data and Q-baseband data;
• an envelope path connected to the voltage supply terminal of the power amplifier;
• an RF path connected to the input end of the power amplifier such that a first signal and second signal indicative of the I-baseband data and Q-baseband data are separately conveyed, respectively, to the envelope path so as to obtain a phase modulated RF signal indicative of the first signal at an end of the RF path, and to the envelope path so as to obtain an envelope signal indicative of the second signal at an end of the envelope path, the phase modulated RF signal provided to the input end of power amplifier, the envelope signal provided to the voltage supply terminal of the power amplifier;
• a switching module disposed between the receiving end and the power amplifier;
• a test signal generator for providing a first test signal and a second test signal to the switching module, the first and second test signals having a periodic waveform, the switching module operable in a first state and in a second state, such that
• when the switching module is operated in the first state, the first test signal is conveyed to the RF path for providing a first further signal indicative of the first test signal to the end of the RF path, and the second test signal is conveyed to the envelope path for providing a second further signal indicative of the second test signal to the end of the envelope path, and
• when the switching module is operated in the second state, the first test signal is disconnected from the RF path and the second signal is disconnected from the envelope path;
• a phase modulator having an input end and an output end, the input end operatively connected to the end of the RF path and the end of the envelope path for obtaining the first and second further signals when the switching module is operated in the first state, the output end operatively connected to the IQ demodulator in the receiver, for providing a demodulated waveform signal having a peak-to-peak amplitude in response to the obtained first and second further signals;
• and
• an adjustable delay device, disposed in one of the RF path and the envelope path, for minimizing the peak-to-peak amplitude.