Sci-Compiler

Case-Study Case-Study, RF, DSP, Signal Processing Case-Study RF DDC NCO CIC CORDIC DSP

Digital Down-Conversion: bringing a carrier to baseband without analog mixers

A large family of measurements does not deliver its information at DC. It arrives riding on a carrier: the free induction decay of an NMR or EPR experiment, the response of a resonant sensor driven at its resonance, the return of a swept optical or acoustic interrogator, the output of an RF front end.

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Case-Study Case-Study, RF, DSP, Signal Processing Case-Study Lock-In RF NCO CORDIC Modulation Low Noise

A lock-in amplifier that lives entirely in the FPGA

A lock-in amplifier is the standard answer to one specific problem: you have a signal you can modulate, and it is far smaller than the noise sitting on top of it.

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Case-Study Case-Study, RF, DSP, Signal Processing Case-Study Goertzel Impedance Spectroscopy RF DSP Resources

Watching a handful of frequencies without paying for an FFT

Electrochemical impedance spectroscopy measures a cell at a dozen or so discrete frequencies. A resonant sensor is interrogated at its resonance and at two points on the skirt.

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Case-Study Case-Study, DSP, Signal Processing, Trigger Case-Study Matched Filter FFT Fast Convolution Trigger SNR

A matched filter at full sampling rate, using fast convolution

If you know the shape of the pulse you are looking for, the filter that maximises the signal-to-noise ratio at the moment of detection is the matched filter: correlate the incoming stream with a time-reversed copy of that shape.

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Case-Study Case-Study, DSP, Signal Processing, Monitoring Case-Study FFT Windowing Spectrum Microphonics Monitoring

Continuous spectral monitoring: finding a line that should not be there

Some of the most useful measurements an instrument makes are not of the thing it was built to measure. A cryostat develops microphonics from a pump that was fine last month.

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Case-Study Case-Study, DSP, Signal Processing, Detector Case-Study Averaging Pump-Probe LIDAR ToF Template SNR

Coherent averaging for repetitive signals, with pile-up thrown away

Whenever a measurement can be repeated on demand, averaging is the cheapest signal-to-noise ratio available. Pump-probe spectroscopy, time-of-flight measurement, LIDAR return profiling, ultrasound, laser-induced breakdown, and the routine business of extracting a detector’s pulse shape all share the same structure: fire something, capture the response, do it again.

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Case-Study Case-Study, Signal Generation, Testing, DSP Case-Study Noise Pink Noise PRNG Testing Signal Generation Dither

Noise you can specify: choosing the right disturbance for a test

“Add some noise and see if it still works” is one of the most common things said about a signal-processing design, and one of the least precise.

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Case-Study Case-Study, Multi Channels, Design Flow, DSP Case-Study TM Time Multiplexing X2730 500 MS/S Concepts

Time multiplexing: what a TM signal is and what a lane means

Every block in the Sci-Compiler library now exists in two versions, and the second one is marked TM. Understanding what that means takes about ten minutes and saves a great deal of confusion, because TM is one mechanism that solves two quite different problems, and the mechanism cannot tell you which of the two you are using it for.

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Filter cs: DSP