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 investigates some state-of-the-art energy harvesting ICs from Linear Technology. The LTC3105 is a highly efficient 400mA Step-Up DC/DC Converter with Maximum Power Point Control and 250mV Start-Up. After exploring the IC’s internal block diagram, the evaluation board for this energy harvesting chip is presented. Various experiments, including the calculation of efficiency, maximum power delivery, start-up behavior and MPPC are presented. As a last experiment, a two stage energy harvesting setup using a solar panel and a super-capacitor capable of charging an iPhone is demonstrated.
The second IC of interest is the LTC3109 which is an Auto-Polarity, Ultralow Voltage Step-Up Converter and Power Manager Energy Harvesting chip. The block diagram and the evaluation board of this IC is presented. The ultra-low voltage capability of the circuit is demonstrated through the use of a Peltier cooler thermo-electric component to generate a 5V output voltage. As a final experiment, several ice cubes are used in conjunction with the thermo-electric generator in order to harvest enough energy to charge an iPhone for 30 seconds.
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.
In this episode Shahriar extensively reviews the Rigol DSA1030A-TG3 Spectrum Analyzer. A wide variety of experiments are performed using the Rigol spectrum analyzer to serve both as a tutorial to use the instrument and to demonstrate its capabilities. Some measurement results are also performed using other calibrated instruments to verify the accuracy of the spectrum analyzer. The Rigol DSA1030A-TG3 can be purchased directly from Rigol Inc.
The following experiments are performed:
1) Signal amplitude, frequency and phase-noise measurements. 2) Low amplitude signal measurements (< -130dBm). 3) Low frequency measurement capabilities (< 9kHz). 4) PRBS length calculations and characterization. 5) Wireless 2.5GHz FM signal transmission and demodulation. 6) Attenuator and band-pass filter response measurements. 7) Amplifier bandwidth and output compression measurements. 8) Calibration and measurements of VSWR using the tracking generator. 9) Characterization of the tracking generator signal quality.
In this episode Shahriar presents a tutorial on the design and characterization of a single-stage low-noise bipolar amplifier suitable for audio applications. Given a set of specifications, a common-emitter topology is investigated. The circuit employs a beta-insensitive biasing scheme which is simultaneously optimized for maximum output swing. The small-signal gain of the circuit is calculated and the bandwidth is set for audio frequencies. A non-inverting operational amplifier is used as a second stage to achieve the desired overall gain. The circuit is assembled on a breadboard where the gain and bandwidth are measured and compared with design specifications. As the final experiment, the circuit is used to amplify signals from a microphone. All documents can be downloaded from here.
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.