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Tag Archives: delta-sigma
How Delta-Sigma Works, part 3: The controls-system perspective
This post is part of a series on delta-sigma techniques: data converters, modulators, and more. A complete list of posts in the series are in the How Delta-Sigma Works tutorial page. In the first installment of How Delta-Sigma Works, I presented … Continue reading
Humbled by a sine wave oscillator
The old saw goes, “oscillators don’t, amplifiers do”, but that’s an analog saying. It doesn’t apply to the digital world. After all, digital is easy, while analog is hard, right? (Be careful not to answer too quickly!) For the last … Continue reading
Posted in Design Notes, Projects
Tagged Agile, delta-sigma, design, FPGA, iambic, keyer, sine wave, test-driven development, theory
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How Delta-Sigma Works, part 2: The Anti-Aliasing Advantage
This post is part of a series on delta-sigma techniques: analog-to-digital and digital-to-analog converters, modulators, and more. A complete list of posts in the series are in the How Delta-Sigma Works tutorial page. Today, let’s take another look at delta-sigma conversion. The … Continue reading
Posted in Design Notes
Tagged adc, anti-aliasing, delta-sigma, design, filter, theory, tutorial
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How Delta Sigma Works, part 1: Introducing the Delta Sigma Modulator
Today I’d like to turn to the fascinating topic of delta-sigma techniques. Delta-sigma is best known for its use in analog-to-digital and digital-to-analog converters, but it also has a potent role in digital signal processing and even in analog applications. By its nature, delta-sigma can reduce the amount of analog circuitry needed in a radio or other electronics, and what is left is often simpler and cheaper than what would otherwise be required.
Beyond that, delta-sigma techniques are nifty! The core concept is counter-intuitive at first glance, yet it offers all kinds of powerful applications. Continue reading
The Plan
I’ve been thinking for some time about a DSP-based ham radio. After
considering and discarding more grandiose schemes, I was inspired by my
Norcal 40A. It and the original Norcal 40 are fairly simple and highly
reproducible (thousands were built). However, performance was not
sacrificed in the name of simplicity. Instead, the rig was carefully
designed to make the most of its NE602 mixers and crystal filter.
Why not try for the same goals in a DSP-based rig? In theory, one should
be able to subsume all of the IF and most of the RF and baseband into…. Continue reading
Posted in Projects
Tagged delta-sigma, DSP, FPGA, multirate, NorCal 40, radio, SDR, software-defined radio
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