Abstract
A two channel 65 nm CMOS RF-waveform characterizer is presented that enables multi-harmonic Adaptive Matching Networks (AMN) or Adaptive Digital Pre-Distortion (ADPD) in RF-power amplifiers. The characterizer measures the DC component and the first 3 harmonics of RF signals by applying a DFT to 8 (ideally) equally spaced quasi-DC output voltages. Conventionally in these types of systems accuracy is limited by sample timing accuracies, which in our case are mainly due to delay cell mismatch. We introduce a novel way to cancel delay cell mismatch, that significantly increases measurement accuracy at the cost of only a small power and area increase. The RF-waveform characterizer achieves 6.8-bit measurement linearity together with a (clock feedthrough limited) 24 dB SFDR. The measured power consumption for our proof-of-principle demonstrator is 18.6 mW at a maximum input signal frequency of 1.1 GHz under continuous operation.
Original language | English |
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Article number | 8481701 |
Pages (from-to) | 1834-1838 |
Number of pages | 5 |
Journal | IEEE transactions on circuits and systems II: express briefs |
Volume | 65 |
Issue number | 12 |
Early online date | 4 Oct 2018 |
DOIs | |
Publication status | Published - 1 Dec 2018 |
Keywords
- Discrete Fourier transform (DFT)
- Signal sampling
- Power amplifiers
- Signal characterization
- Delay spread cancellation
- CMOS integrated circuits