Abstract
Hard-switched mixers have attractive linearity and noise properties, but are plagued by spurious responses due to the harmonic content of square-wave signals. Harmonic rejection mixers (HRMs) reject (some of) these responses and can be constructed combining polyphase mixing and amplitude weighting. This paper presents a generalized model for the analysis of the of such HRMs, based on circular convolution. We show that the effective signal can be modeled as a periodic Dirac impulse filtered by a time-discrete filter. For a multi-stage system, this filter consists of multiple stages as well, and the coefficients of each stage can be found simply by inspection. The total is shown to be the sum (in dB) of the rejection of the individual filtering stages, highly simplifying analysis and design of HRMs
Original language | English |
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Number of pages | 5 |
Journal | IEEE transactions on circuits and systems II: express briefs |
Early online date | 14 Jan 2021 |
DOIs | |
Publication status | E-pub ahead of print/First online - 14 Jan 2021 |
Keywords
- Circular convolution
- Frequency conversion
- Harmonic rejection
- Mixer