test time efficient group delay filter characterization technique using a discrete chirped...
TRANSCRIPT
![Page 1: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/1.jpg)
Test time efficient group delay filter characterization technique using a discrete chirped excitation signal
2016 International Test Conference
November 16th
Peter Sarson
![Page 2: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/2.jpg)
2
Outline
What problem are we trying to resolve How to measure phase based metrics What does a discrete chirp buy us How to generate a chirp Implementation Measurements Correlation and stability Conclusion
![Page 3: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/3.jpg)
3
What problem are we addressing
Produce a Group Delay production style test• That gives full characterization data• That is faster than the standard approach• That can be reused easily like an IP Block
Save coding time for future projects Remove last minute requests for
characterization tests
![Page 4: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/4.jpg)
4
What is group delay
group delay is a measure of the slope of the phase response at any given frequency
• Tg = -d /d
Therefore – need to sweep filter frequency range to get characterization data
![Page 5: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/5.jpg)
5
Standard Method
Start and Stop of AWG for each and individual Frequency of interest
Full Digitizer capture for each frequency Long Test Time for a few or many frequencies
![Page 6: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/6.jpg)
What does a discrete chirp buy us
6
![Page 7: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/7.jpg)
Chirp in the Frequency Domain
7
![Page 8: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/8.jpg)
8
How to generate a discrete chirp
By using the coherence formula we can build a discrete chirp using Ff
• Fs/Ft = N/M - Coherence Condition• Ff = Fs/N - Fourier Freq - Resolution• r = 2/N - Phase Resolution
If we build a wavelet by making sinewaves a multiples of Ff we will produce a discrete chirp
![Page 9: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/9.jpg)
9
Phase Calibration
As the starting phase of the AWG is unknown• We need to somehow remove the starting
phase By making a loopback circuit• We can capture the source waveform• and device response• In one capture
Hence subtracting the two removes the starting phase of the AWG
![Page 10: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/10.jpg)
10
Phase Calibration Circuit
![Page 11: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/11.jpg)
11
Production Implementation
![Page 12: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/12.jpg)
12
Filter and Reference extracted
![Page 13: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/13.jpg)
13
Points to note
To get from an FFT to real phase• We need to phase unwrap the signal• If the phase resolution is to small this will
not be possible
The phase response is described as• (t) =0 + 2( f0t + kt2/2)
![Page 14: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/14.jpg)
14
Phase Response
![Page 15: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/15.jpg)
15
Time delay through filter
![Page 16: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/16.jpg)
16
Group Delay Curve
![Page 17: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/17.jpg)
17
Correlation
Frequency(kHz)
Group Delay (us)
Simulation Chirp (ATE) Lab
50 5.4 5.7 5.6
100 4 5.6 5,5
120 3.2 5.5 5.4
![Page 18: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/18.jpg)
Stability
18
![Page 19: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/19.jpg)
Reproducibility
19
![Page 20: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/20.jpg)
Test Time Saving
AWG setup time is 2ms• UTP of waveform is negligible in time• So 5 frequencies for Group Delay is 10ms
Using a chirp• You only setup once• Therefore more frequencies that are of
interest the more the chirp is cost effective
20
![Page 21: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/21.jpg)
Conclusion
Using a chirp for group delay measurements gives reliable, accurate and reproducible results that is not only test time efficient but also gives full characterization data that is priceless to a semiconductor integrated circuit designer.
21
![Page 22: Test time efficient group delay filter characterization technique using a discrete chirped excitation signal](https://reader034.vdocument.in/reader034/viewer/2022051521/587b2c5a1a28ab057d8b53b3/html5/thumbnails/22.jpg)
Confidential © ams AG
Thank you
Please visit our website www.ams.com