In this episode Shahriar takes a close look at an HP/Agilent 5347A 20GHz Frequency Counter and Power Meter. This defective unit does not provide any frequency information from Input 2 which is rated to operate up to 20GHz. Before the teardown and repair attempts, the principle operation of the instrument is reviewed.
The properties of a Step Recovery Diode (SRD) is presented along with the theory and practical aspects of generating a frequency comb. The heterodyne architecture of the frequency counter is explained in detail with the mechanism of detection and calculation of the input frequency.
During the teardown of the unit the synthesizer board, motherboard, power meter reference board and the main RF assembly are shown. The schematic of the synthesizer board and the RF board are also described. The defective component is identified and examined under the microscope. The slides for this episode can be found here.
In this episode, Shahriar upgrades an Agilent 53131A Universal Counter with the OPT-030 which extends its frequency range from 225MHz to 3GHz. The upgrade kit is a replica PCB intended to emulate the behavior of the original Agilent branded option.
The PCB is examined carefully with attention to microwave layout techniques along the signal path. The datasheet of all the parts are reviewed and the reverse-engineered block diagram of the PCB is presented. The expected behavior of the PCB is then measured in both small-signal and large-signal operation using an active 3GHz probe. The PCB is then installed inside the unit and the functionality of the instrument is verified within its specifications. All the documents presented in the video can be found here.
In this episode Shahriar repairs an Agilent E4421A synthesized signal generator purchased from eBay. The unit displays the error messages “UNLOCK” and “UNLEVEL”. The cause of failure is investigated and traced. Alongside the repair efforts, the internal construction and components of the synthesizer are also presented. A short tutorial on the advantages and disadvantages of using a Darlington transistor is also presented as well as the schematic of a simple Darlington based voltage regulator. The documents for this tutorial can be found here.
In this episode Shahriar demonstrates the functionality and applications of an Agilent 11896A Polarization Controller. Various fiber optic communication methods are presented. This includes the use of complex modulation schemes (such as PAM and QAM for coherent receivers), polarization division multiplexing (PDM), wavelength division multiplexing (WDM), and spatial division multiplexing (SDM). The concept of light polarization is demonstrated by using a pair lenses from a consumer theater 3D glasses and two blue LEDs with uncorrelated lighting patterns.
In order to test the polarization controller, a solid-state laser source, SMF fiber with APC/PC connectors as well as a polarization beam splitter is presented. By using a pair of optical power sensors, the functionality of the polarization controller is verified. Finally, the teardown of the unit is presented and the method to achieve polarization control is observed.
The fiber optic communication overview document can be downloaded here. I’d also like to acknowledge my colleague and friend Dr. Timo Pfau for his expertise and consult on fiber optic communication methods.
In this episode Shahriar goes through the teardown and repair process of a Fluke 196B Handheld ScopeMeter. This unit, which has been purchased as a “dead” unit from eBay, is examined for faults. During the teardown, various PCB components, architecture and design ispresented. The performance and functionality of the unit is verified with a few brief experiments. Finally, the schematic and block diagram of the Fluke 196B is explored for the finer details of its design and operation.
This is "The Signal Path dot com"! An electrical engineering video blog for students, hobbyists and hackers. I do equipment reviews, teardowns, circuit design tutorials, testing procedures and more! Subscribe to my RSS, join the community forum and participate in the discussions.