Dave Van Ess is a principal applications engineer with Cypress Semiconductor, San Jose, Calif. He received a BSEE from the University of California at Berkeley. Email address: dwv@cypress.com
15 results found for Dave Van Ess, displaying items 1 - 15
October 1, 2009[Analog/Mixed-Signal Design] Synchronous Detection Plays A Role In Better Analog Design
Synchronous detection is a measurement method where a stimulus is modulated with some frequency and the response is demodulated to bring the signal back down to base band. Performed when a dc stimulus is not acceptable, it’s widely used in medical and scientific signal conditioning and in capacitive, inductive, or complex impedance measurements. It also allows for the collection of signals in a high-noise environment. Densitydomain signal...
August 13, 2009[Analog/Mixed-Signal Design] Use DSM To Shift Your Signal Processing
First, to those of you who have sent me e-mails about my delta-sigma series, thank you. I appreciate the kind words and notification of errors. I also received a few e-mails from some readers, mostly grad students, wanting to let me know they are way smarter than me. They included questions guaranteed to confirm their position— for example, what effect does first- through third-stage parasitic capacitance have on overall differential non-linearity performance ...
June 2, 2009
[Analog/Mixed-Signal Design] What's Next For Programmable Devices?
Engineers seldom have to design with discrete components anymore. Integrated ADCs, DACs, high-speed amplifiers, and switch capacitor ICs are now readily available. The most truly amazing advances, however, have been in digital design. The shortage of logic chip designers and the expense of design has led to development along two different avenues: microprocessors and programmable logic. Now, though, these avenues are merging.
April 23, 2009[Analog/Mixed-Signal Design] Using Delta-Sigma Can Be As Easy As ADC (Part 5)
My last column showed how a single-stage delta-sigma modulator (DSM) produces an output that is a sum of the low pass-filtered input signal and the high pass-filtered quantization noise (see “Part 4,” Jan. 29, p. 18; ED Online 20485). The primary difference between a filter and a DSM is that a filter feeds back its output while the DSM feeds back its quantized output. If ...
March 3, 2009
[Analog/Mixed-Signal Design] Build SincK Decimators
There’s a lot of talk in engineering publications these days about decimation filters, which are easy to construct when understood. This article will attempt explain their operation and show the steps needed to construct one. Let’s start with a straightforward filter that sums 16 values together.
January 29, 2009[Analog/Mixed-Signal Design] Using Delta-Sigma Can Be As Easy As ADC (Part 4)
Based on the amount of e-mail I received after Part 3 of this series (Nov. 7, 2008, p. 18; www.electronicdesign.com, ED Online 19948), many of you have already guessed that an incremental integrator is really just a delta-sigma modulator (DSM). Well, you’re right! It actually is a continuous-time delta-sigma modulator....
December 4, 2008
[Analog/Mixed-Signal Design] Use Software Filters To Reduce ADC Noise
Let’s say you chose a particular microcontroller for its 12-bit analog-to-digital converter (ADC). You built up your system, and although the ADC gives you 12 bits of resolution, the lower couple of bits are frustrating and “unreliable,” to put it nicely. Fortunately, you can reduce or remove this noise with one of two different types of software filters.
November 7, 2008[Analog/Mixed-Signal Design] Using Delta-Sigma Can Be As Easy As ADC (Part 3)
Part 2 of this series showed how a dual-slope integrator could fix the major limitations of a single slope converter, and I received several e-mails in response (August 28, p. 18, ED Online 19512). For example, Harry Bissel of WTC questioned my choice of polyester capacitors for low dielectric absorption. “I don’t believe that ‘Polyeste’ belongs in your list of...
August 28, 2008[Analog/Mixed-Signal Design] Using Delta-Sigma Can Be As Easy As ADC (Part 2)
In my previous column, I took a historical approach to delta-sigma modulation with the single-slope converter (May 8, p. 18, ED Online 18747). Jim Williams of Linear Tech responded, and he sent me a copy of a 1949 article by D.H. Wilkinson on single-slope analogto- digital converters (ADCs). “I’m aware of their obvious weaknesses, but the simplistic elegance of the...
June 6, 2008
[Analog/Mixed-Signal Design] Squeeze 10-Bit Performance From An 8-Bit ADC, Part 2: Triangular Dithering
You don’t want to burden your design with the extra cost of a higher-resolution analog-to-digital converter (ADC). But because of board-space limitations, adding an external ADC may not be acceptable. Fortunately, you can get 10-bit performance with an 8-bit ADC by implementing triangular dither.
May 8, 2008[Analog/Mixed-Signal Design] Using Delta-Sigma Can Be As Easy As ADC
As an application engineer, I spend a lot of time convincing customers that a delta-sigma modulating analog-to-digital converter (ADC), or DSM, would be the best choice for their particular application. Then they come up with all sorts of excuses for why they prefer a successive-approximation ADC. I’ve come to the conclusion that they prefer successiveapproximation ADCs because they fundamentally don’t understand how a DSM works, perhaps because DSMs involve...
May 5, 2008
[Analog/Mixed-Signal Design] Squeeze 10-Bit Performance From An 8-Bit ADC, Part 1: Additive Dithering
You don’t want to burden your design with the extra cost of a higher-resolution ADC. And because of board-space limitations, adding an external ADC may not be acceptable. Fortunately, you can get 10-bit performance with an 8-bit ADC by averaging multiple samples. This process is called oversampling.
February 28, 2008[Analog/Mixed-Signal Design] Squeeze 10-Bit Performance From An 8-Bit DAC
Few things are more frustrating than a requirement for some feature that exceeds the ability of your present hardware. Say you’re designing a product that has historically required an 8-bit digital-to-analog converter (DAC). Conveniently integrated on the system microcontroller, the DAC has never been a problem until marketing suddenly insists that it is absolutely necessary for the DAC to output 10 bits. Of course, it’s too late to change microcontrollers, and...
June 9, 2005[Ideas For Design] Programmable Analog Current Source Uses Switched Capacitors
Switched-capacitor blocks are easily configured to be integrators. When configured as an integrator, a switch-capacitor block can function as an op amp. Closed-loop stability is achieved by parametrizing the capacitor values and sample frequency, which allow for precise gain-bandwidth control. Adding an external pass transistor and current-setting resistor enables easy construction of a programmable current source. Figure 1 shows...
