TSP #258 – TEGAM AVM-2000 100nV – 1000V Null Detector / Nanovoltmeter Repair, Teardown & Experiments

March 8, 2025 No comments

In this episode Shahriar takes a look at a faulty PPM (TEGAM) Null Detector. With its massive dynamic range (10 orders of magnitude!) this instrument is capable of nano-Volt range measurements. Unfortunately the unit is faulty and does not display or measure anything at the input.

The unit requires a battery for operation (6V Lead-Acid) which can be bypassed by using a 7.4V LiPo battery. The unit powers on and the power supply section is fully functional. Detailed block diagrams and schematic analysis of the unit is discussed during the video.

The analog front-end is also verified to be functional through internal measurements and although there is digital communication between the various internal modules, the ADC only transmits a fixed (faulty) data sequence to the front-panel. The fault is traced to be a corrupted firmware which the manufacture does not agree to share.

Thanks to a helpful internet friend, firmware from a working unit is extracted and compared with the faulty instrument. It becomes clear that the corrupted FLASH memory is responsible. After transferring the calibration coefficients to the modified new firmware the unit comes back to life! Several measurements showcase the units capabilities and functionality.

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TSP #257 – Siglent SNA5000A 8.5GHz 4-Port VNA Mixer & TDR Application Review & Experiments (II)

March 2, 2025 No comments

In this episode Shahriar continues the review of the Siglent SNA5000A series vector network analyzer. You can also watch the Part 1 review & teardown of this instrument:

https://youtu.be/6vHX0moZUFg

The Siglent SNA5000A continues to receive new features and upgrades:

https://siglentna.com/vector-network-analyzer/sna5000a/

This review is organized as follows:

00:00 – Introductions
02:12 – Scaler Mixer Measurement application & setup
07:33 – Mixer s-parameter & power calibration routines
11:14 – I/Q down & up-converter frequency response characterization
16:01 – Power sweeps and conversation gain implications
19:32 – Frequency doubler measurement setup & characterization
23:07 – TDR measurement application, setup & calibration
26:24 – Characterization of a SATA backplane differential channel
29:13 – Eye diagram plots, data-rate, PRBS & mask setup
32:23 – Equalization, pre-emphasis, jitter & CTLE
36:10 – Concluding remarks

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TSP #256 – Mysteries of Optical HDMI Cables – Tutorial, Teardown & Analysis of Inexpensive Optics

January 29, 2025 No comments

In this episode, Shahriar takes an in-depth look at the design and architecture of optical HDMI cables, which significantly extend the reach of traditional HDMI 2.0 twisted-pair copper links at a low cost.

The fundamentals of HDMI high-speed data transmission are explored, with a focus on the TMDS (Transition Minimized Differential Signaling) standard. The challenges of transitioning from twisted pairs to optical lanes are examined, highlighting the role of VCSELs and PIN photodiodes. Optical modules are analyzed in detail, emphasizing free-space optics and optical confinement techniques used with lasers and detectors. The received high-speed lane’s eye diagram is captured, and the VCSELs’ optical wavelength is confirmed to be 850 nm.

Additionally, the TX (driver) and RX (TIALA) chips are inspected under a microscope, revealing the VCSEL and photodetector arrays. The overall electronic architecture is then discussed in greater detail.

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TSP #255 – Terahertz Material & Dielectric Characterization – EM Labs 330GHz Fabry-Perot Resonator

January 19, 2025 No comments

In this episode Shahriar takes a look at a terahertz characterization technique using a Fabry-Perot resonance chamber made by EM Labs:

https://www.emlabs.jp/en/1-8-fpr.php

The chamber is able to measure dielectric constant and loss tangent with remarkable accuracy and prevision, ideal for materials with tan δ (Df) of 0.01 or less. This tutorial and review video is organized as follows:

00:00 – Introductions
00:45 – Dielectric Constant theory, equations and practical importance
04:54 – Measurement techniques using S-Parameters and resonance chambers
08:16 – Fabry-Perot resonator techniques for accurate Dk & Df measurements
11:04 – THz measurement setup including Fabry-Perot resonator, Keysight Streamline VNA and VDI frequency extenders
13:36 – Design challenges and features of the EM Labs Fabry-Perot resonator
16:02 – Software setup, resonator calibration and preparations
19:22 – Preparing, aligning and measuring samples, organic PCB laminate and prepreg
23:19 – Measuring ultra-low loss materials in J-Band
24:21 – Analyzing anisotropic material properties as a function of orientation
26:27 – Concluding remarks

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TSP #254 – X-Ray Florescence CMI900 Oxford Instruments Teardown, Repair & Experiments (Part 1)

December 21, 2024 No comments

In this episode Shahriar takes a look at an X-Ray florescence machine. The CMI900 Oxford Instruments unit is not only capable of elemental analysis and identification, it can also measure the thickness of various coatings which is particularly interesting for electronics.

Unfortunately the already-non-functional unit has been further damaged in transit due to poor packaging. In this first video we dive into the repair of the unit and accompanying PC. The unit has several problems both mechanical & electrical and the damage to the PC hosting the unique interface software is also extensive. The teardown and repair procedures are covered in this video.

Stay tuned for the next episode where Shahriar will cover the theory of operation as well as range of measurement experiments.

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