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  1. #1
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    Spectre RF Envelope Simulation for Wireless Transmitter with Switched-Cap Baseband

    Hi,

    I'm designing a wireless transmitter that consists of a DAC, a switched-cap baseband filter and a passive upconverter. I'm trying to simulate the spectral performance (ACLR and EVM) and produce constellation plots using QAM signals. The signals have been generated in MATLAB with RRC pulse shaping or come straight from the Rectangular QAM16 modulator block in rfLib with the RRC implemented in VerilogA.

    Using a transient simply takes too long as the system has 3 distinct clock domains: the sampling rate of the digital signal, fdata, the clock of the switched cap filter, fs, and the frequency of the local oscillator driving the upconverter, LO. I was told that envelope following analysis was the way to go, but I don't know how to set it up in my case.

    I have read all relevant workshops provided within SpectreRF but they only cover the simple case where you have 1 LO and the baseband frequency. How can I configure the simulator now that I basically have two large tones at fs and LO plus the DAC generating the baseband signal? (please note that both fs and LO are square-wave signals with 25% duty cycle)

    Thank you in advance!

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  2. #2
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    pancho_hideboo's Avatar
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    Re: Spectre RF Envelope Simulation for Wireless Transmitter with Switched-Cap Baseban

    Simply do one tone(LO) envelope analysis.
    fs and DAC output are treated as baseband signal.
    That’s all.


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