Archive for Tutorial

Starlink Dish Phased Array Design, Architecture & RF In-depth Analysis

In this episode Shahriar takes a detailed look at the Starlink Satellite Dish. The dish was kindly sent by Ken who has done his own initial teardown here.

The dish is analyzed layer by layer from the radome down to individual integrated circuits. The RF design, system architecture and many aspects of the overall product are described in details. An X-Ray of the RF stack is also shown which further explores the design of the array.

Tutorial on Theory, Characterization & Measurement Techniques of Phase Noise

In this episode Shahriar demonstrates the fundamentals of Phase Noise. The theory behind phase noise is presented both from a time-domain and frequency domain points of view. Various mathematical equations which represent phase noise behavior is also presented.

Phase noise measurement challenges and techniques are covered. Capabilities and limitations of different instruments for phase noise characterization is explained. The experiments show AM/PM modulations both in time and frequency domain and their relationships to phase noise measurements. Using a spectrum analyzer the phase noise of several synthesizers are shown. However, it is clear that the phase noise of an ultra-clean 1-GHz reference signal cannot be measured using traditional methods.

The concept of cross-correlation is introduced as a means of measuring phase noise below the phase noise of the measurement instrument. The block diagram of the an Agilent Phase Noise Analyzer is presented followed by a short teardown. The measured phase nose of the ultra-clean 1-GHz source is shown using correlation techniques which matches the datasheet.

Teardown & Experiments with Agilent mm-Wave W-Band (75 – 110GHz) T/R Module & Controller

In this episode Shahriar does a deep dive into the operation and architecture of Agilent/HP mm-Wave Extension Modules and Controller. The Agilent 85015A and W85104A work in conjunction and as the front-end for a W-Band (75-110GHz) S-Parameter T/R set. Although the mainframe system (HP 8510 Network Analyzer) is not available, a close look at the block diagrams reveals that the controller can be driven via external synthesizers to provide LO and RF signals. The detailed explanation of the entire system is presented from the ground up.

The full teardown of the mm-wave controller and T/R module are also presented and by reverse engineering the GPIB commands, the T/R module is brought to life. Several experiments show the full functionality of the system including a high-resolution CW radar demonstration.

One Simple Wish Foundation:

Texas Instrument TI-PMLK Power Management/Conversion Kit Tutorial, Review & Experiments

In this episode Shahriar presents a meticulously prepared set of educational lab kits on Power Conversion by Texas Instruments. These kits include  Buck, Boost, LDO and Buck-Boost power conversion courses complete with a beautiful set of lab instructions and PCBs. Each kit describes up to 7 different exercises which demonstrates various aspects of power conversion characterization and design challenge.

In particular the Buck Lab kit is examined. The PCB is populated with two different Buck DC-DC converters which are carefully described in the lab kit. The first experiment of the lab kit is performed which involves measuring system efficiency under various load conditions and switching frequency. The inductor current, MOSFET switching voltage and output waveform are examined on the oscilloscope.

How Do Purely Passive Watt-Meters Work? (Giveaway Results & More Giveaway! December 2018)

In this episode Shahriar demonstrates the principle of operation of a purely passive Weston watt-meter manufactured in the 1950’s in Newark, NJ, USA. This watt-meter makes no use of active devices (tube or solid-state) and yet is able to measure real-power both at DC and AC.

The teardown of the unit shows the construction of two coils interacting to advance the needle on the display. One coil produces a magnetic flux proportional to the current input and the other coil produces a magnetic flux propositional to the voltage. The interaction of the flux moves the needle proportional to the total power which is the product of current and voltage. The instrument is then used in conjunction with a power supply and electronic DC load to verify its functionality.

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