The Correlation and Application between IMR and ACPR for Broadband Signals in Microwave and Millimeter-Wave Frequencies
Date Issued
2005
Date
2005
Author(s)
Chen, Wei-Chien
DOI
en-US
Abstract
Two-tone test inter-modulation ratio (IMR) is the common characterization of nonlinear circuits, but adjacent channel power ratio (ACPR) is closer to represent the nonlinearity in modern complicated standards requirements. However, the time-consuming and high-cost drawbacks of direct measuring ACPR for different modulation types make it less attractive.
Therefore, this thesis describes the correlation and application between IMR and ACPR for multi-standard broadband signals in microwave and millimeter-wave frequencies. For microwave frequencies, the verification of third-order IMR (IM3R) and multi-ACPR (M-ACPR) correlation is demonstrated first at 1.95 GHz and 2.4 GHz for 3.84 MHz and 16 MHz broadband signals, respectively. Then, the extension to millimeter-wave frequency at 44 GHz is also implemented for these broadband signals. As for the third-order nonlinear system, these measured data show excellent agreement, within ±1 dB, between two-tone and multi-tone tests up to the P1dB point. It is also discussed that if the fifth-order (or higher orders) nonlinearities is considered, the correlation between IM3R and M-ACPR will be closer in large signal region.
As for the application, the implementation of IMD sweet spots and what we called ACPR sweet spots is done by both HBT commercial power amplifier and CMOS pre-distortion power amplifier at 2.4 GHz. A series of experiments reveal high correlated between the adjustment of first and second stage’s bias points for both IMD and ACPR sweet spots. The average function from different PDF is also introduced to correlate the IMD sweet spots and ACPR sweet spots precisely. This reveals that as long as the correlation between IMD products and ACPR can be found, the ACPR with different digital modulated signal can be predicted by measuring its PDF and then modifying IMD products in the same frequency band.
Subjects
諧波互調失真比
鄰近通道功率比
寬頻訊號
毫米波
IMR
ACPR
Broadband Signal
Millimeter-Wave Frequencies
Type
thesis
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