Feedforward amplitude cancellation topology for multi-carrier applications

A multi-carrier receiver system, comprising:

• a frequency conversion circuit for generating an intermediate frequency (IF) multi-carrier signal based on a transmission frequency multi-carrier signal;
• a feedforward cancellation loop for generating an amplitude corrected multi-carrier signal based on the IF multi-carrier signal such that the amplitude corrected multi-carrier signal has a reduced dynamic range with respect to the IF multi-carrier signal;
• and
• a primary analog to digital (A/D) converter for generating a digital multi-carrier signal based on the amplitude corrected multi-carrier signal;
• wherein the feedforward cancellation loop includes:
• a secondary A/D converter for generating a digital cancellation signal based on the IF multi-carrier signal;
• a level adjustment circuit coupled to the secondary A/D converter for digitally adjusting the digital cancellation signal such that carriers in the digital cancellation signal correspond to carriers in the IF multi-carrier signal having power levels above a predetermined threshold;
• and
• a digital to analog (D/A) converter for generating an analog cancellation signal based on the digital cancellation signal.

A multi-carrier receiver system, comprising:

• a frequency conversion circuit for generating an intermediate frequency (IF) multi-carrier signal based on a transmission frequency multi-carrier signal;
• a feedforward cancellation loop for generating an amplitude corrected multi-carrier signal based on the IF multi-carrier signal such that the amplitude corrected multi-carrier signal has a reduced dynamic range with respect to the IF multi-carrier signal;
• a primary analog to digital (A/D) converter for generating a digital multi-carrier signal based on the amplitude corrected multi-carrier signal;
• a primary channelizer coupled to the primary A/D converter;
• a cancellation feedback loop connected between the primary channelizer and the level adjustment circuit for providing cancellation feedback to the level adjustment circuit;
• and
• a delay module for delaying the IF multi-carrier signal based on a processing time of the feedforward cancellation loop.

A multi-carrier receiver system, comprising:

• a frequency conversion circuit for generating an intermediate frequency (IF) multi-carrier signal based on a transmission frequency multi-carrier signal;
• a feedforward cancellation loop for generating an amplitude corrected multi-carrier signal based on the IF multi-carrier signal such that the amplitude corrected multi-carrier signal has a reduced dynamic range with respect to the IF multi-carrier signal;
• and
• a primary analog to digital (A/D) converter for generating a digital multi-carrier signal based on the amplitude corrected multi-carrier signal;
• wherein the frequency conversion circuit includes:
• a first mixer for generating a preliminary IF multi-carrier signal based on the transmission frequency multi-carrier signal and a first oscillation signal;
• a transmission filter for filtering a predetermined transmission bandwidth from the preliminary IF multi-carrier signal;
• and
• a second mixer for generating the IF multi-carrier signal based on the preliminary IF multi-carrier signal and a second oscillation signal.

A feedforward cancellation loop comprising:

• a secondary A/D converter for generating a digital cancellation signal based on an intermediate frequency (IF) multi-carrier signal;
• a level adjustment circuit coupled to the secondary A/D converter for digitally adjusting the digital cancellation signal such that carriers in the digital cancellation signal correspond to carriers in the IF multi-carrier signal having power levels above a predetermined threshold;
• and
• a digital to analog (D/A) converter for generating an analog cancellation signal based on the digital cancellation signal.

A method for receiving a transmission frequency multi-carrier signal, the method comprising the steps of:

• generating an intermediate frequency (IF) multi-carrier signal based on the transmission frequency multi-carrier signal;
• generating an amplitude corrected multi-carrier signal based on the IF multi-carrier signal such that the amplitude corrected multi-carrier signal has a reduced dynamic range with respect to the IF multi-carrier signal;
• generating a digital multi-carrier signal based on the amplitude corrected multi-carrier signal;
• generating a digital cancellation signal based on the IF multi-carrier signal;
• and
• digitally adjusting the digital cancellation signal such that carriers in the digital cancellation signal correspond to carriers in the IF multi-carrier signal having power levels above a predetermined threshold.

A method for receiving a transmission frequency multi-carrier signal, the method comprising the steps of:

• generating an intermediate frequency (IF) multi-carrier signal based on the transmission frequency multi-carrier signal;
• generating an amplitude corrected multi-carrier signal based on the IF multi-carrier signal such that the amplitude corrected multi-carrier signal has a reduced dynamic range with respect to the IF multi-carrier signal;
• generating a digital multi-carrier signal based on the amplitude corrected multi-carrier signal;
• generating a digital cancellation signal based on the IF multi-carrier signal;
• digitally adjusting the digital cancellation signal such that carriers in the digital cancellation signal correspond to carriers in the IF multi-carrier signal having power levels above a predetermined threshold;
• and
• generating an analog cancellation signal based on the digital cancellation signal.