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Rohde and Schwarz AMIQ Modulation Generator Teardown
& Schwarz AMIQ Modulation Generator - Teardown and Analog Deep Dive - Introduction - The Rohde & Schwarz AMIQ Modulation Generator - WinIQSim Software - Inside the AMIQ - The Signal Generation PCB - Analog Signal Generation Architecture: Fixed vs Variable DAC Clock - Internal Reference Clock Generation - DAC Clock Synthesizer - I/Q Output Skew Tuning - Variable Gain Amplifier - Internal Diagnostics - Efficient Distribution of Configuration Signals - Conclusion - References Introduction Every few months, a local company auctions off all kinds of lab, production and test equipment. I shouldn’t be subscribed to their email list but I am, and that’s one way I end up with more stuff that I don’t really need.
With WinIQSim, you can select one of the popular communication protocols from the late nineties and early 2000s, fill in digital framing data, apply all kinds of distortions and interferences, compute the I and Q waveforms and send it to the AMIQ. For an arbitrary waveform generator, it makes more sense to run the DAC at whichever clock speed is sufficient to meet the Nyquist requirement of the desired signal and provide a number of different filtering options. In modern fractional PLLs, instead of using a regular DAC, one could use a high-order sigma-delta unit to create a pulse density modulated output with the noise pushed to higher frequencies and a low pass filter that can be less aggressive.
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