Signal conditioning can prepare a sensor’s output for digitization. In part 1 of this series, we looked at a typical analog signal chain that you can use in conjunction with analog-to-digital converters (ADCs) or digital-to-analog converters (DACs). A key building block of the analog signal chain is the operational amplifier (op amp), shown in its […]
FAQ
How to compare EMI absorption materials with a cookie tin
Product enclosures have frequency resonances that can produce unwanted EMI. Absorption materials in the cavity can reduce EMI. Use a cookie tin to compare materials before inserting them into your product. As operating frequencies approach microwaves, enclosures can appear as resonant cavities and amplify EMI emissions. When I was working on space shuttle communications systems, […]
How to choose analog-signal-chain components: part 1
Signal conditioning can prepare a sensor’s output for digitization. In a previous series, we looked at the analog-to-digital converter (ADCs) and sources of error that occur within the device. Of course, errors can creep in upstream of the ADC along the analog signal chain as the signal to be digitized is acquired and conditioned. Q: […]
Understanding ADC specs and architectures: part 5
ENOB describes an analog-to-digital converter’s performance with respect to total noise and distortion. In the earlier parts of this series on analog-to-digital converters (ADCs), we looked at the basics (part 1); gain error, offset error, and differential nonlinearity (part 2); and integral nonlinearity (part 3); and then we looked at some ADC topologies and introduced […]
Understanding ADC specs and architectures: part 4
The AC performance of an analog-to-digital converter depends on its architecture. In part 3 of this series, we discussed the integral nonlinearity (INL) error of an analog-to-digital converter (ADC), noting that gain, offset, and INL error all contribute to the total unadjusted error. This metric provides an overall view of an ADC’s DC performance. Q: What about the AC […]
Understanding ADC specs and architectures: part 3
Integral nonlinearity tracks the cumulative effects of an ADC’s differential nonlinearity. In part 2 of this series, we discussed several sources of error in an analog-to-digital converter (ADC), including gain, offset, missing-code error, and differential nonlinearity (DNL). We concluded with an illustration of a waveform with varying levels of DNL superimposed on the staircase representing […]
Understanding ADC specs and architectures: part 2
Specifications such as gain error, offset error, and differential nonlinearity help define an analog-to-digital converter’s performance. In part 1 of this series, we discussed an ideal analog-to-digital converter (ADC), noting that it would have infinite resolution and bandwidth. Then we looked at the real world of practical inverters and how their resolution, expressed in a […]
Understanding ADC specs and architectures: part 1
Analog-to-digital converters are the heart of most test equipment, setting the stage for the digital processing of analog signals. Several posts over the past year or so have involved digital signal processing. For example, we have covered the fast Fourier transform (FFT), the inverse FFT, and discrete convolution. To perform these operations on real-world signals, […]
Review: Micsig TO3004 tablet oscilloscope
If you’re looking for a portable oscilloscope for field troubleshooting or for demonstrations, look at the Micsig TO series. Here’s my take on the four-channel 300 MHz variant, TO3004. The Micsig TO3004 oscilloscope (Figure 1) is an 8-bit, four-channel, tablet-sized portable oscilloscope that’s also available with 100 MHz and 200 MHz varieties with two or […]
How to use convolution to implement filters: part 4
A windowed sinc function can implement a low-pass filter, and a two-dimensional convolutional filter can blur or sharpen images. In part 3 of this series, we introduced a low-pass filter based on the Sinc function and described the need for windowing to compensate for sampling and truncation. Q: How can we apply this filter? A: […]
