The Impact of LO Phase Noise in N-Path Filters
| Autor: | Alyssa B. Apsel, Hazal Yuksel, Zachariah Boynton, Thomas Tapen, Alyosha Molnar |
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| Rok vydání: | 2018 |
| Předmět: |
Physics
Local oscillator Acoustics Capacitive sensing 020208 electrical & electronic engineering 020206 networking & telecommunications 02 engineering and technology Transfer function Band-pass filter Phase noise 0202 electrical engineering electronic engineering information engineering Baseband Radio frequency Electrical and Electronic Engineering Electrical impedance |
| Zdroj: | IEEE Transactions on Circuits and Systems I: Regular Papers. 65:1481-1494 |
| ISSN: | 1558-0806 1549-8328 |
| DOI: | 10.1109/tcsi.2017.2761260 |
| Popis: | As passive mixers (N-path filters) are being used more frequently and in more applications, it becomes increasingly important to understand how various non-idealities affect the performance of passive mixer circuits. One such non-ideality is perturbations in the local oscillator (LO), including phase noise. Here, we consider a basic N-path filter and develop a preliminary model to analyze the effects of LO phase perturbations in shunting N-path filters. We do so by developing a transfer function from phase perturbations in the LO to voltage perturbations on a strong RF signal at the mixer’s RF port. We find that LO phase noise is suppressed where it is strongest (i.e., for small offset frequencies). As a result the RF spectrum’s noise peak does not appear around the signal tone, but rather around the LO frequency, due to the bandpass characteristic generated by a typical capacitive baseband load. These analytical results are verified using numerical and schematic simulation in custom software and Cadence, and they are further confirmed by measurement of a frequency-scaled, board-level implementation of an N-path filter. |
| Databáze: | OpenAIRE |
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