In this episode Shahriar repairs an Agilent 33250A function and arbitrary waveform generator which does not power on. The unit is equipped with a soft power switch which might be responsible for the fault. After a brief look at the unit’s constructions, the fault is traced to a few possible locations.
The schematic of the soft power circuitry is presented and the internal switching power supply is closely examined. After the fault is located, the repair is presented. The block diagram and operation of a current mode DC-DC switching IC is also presented.
In this episode, Shahriar upgrades a Verity visible wavelength monochromator model EP200Mmd to be able to perform automatic scans. The instrument is retrofitted with a stepper motor and a microcontroller which performs wavelength scanning between 225nm to 875nm. The signal from the internal photomultiplier is sampled by the microcontroller and wirelessly sent to the computer. Matlab is used to plot the wavelength response.
The principle operation of a monochromator is thoroughly reviewed starting with the grating mirror behavior. The operation of the photomultiplier is also described. Various mechanical and electronic of the upgraded system is also shown. The presented slides can be found here.
In this world exclusive episode, Shahriar takes a close look at the all new Tektronix Real-Time USB Spectrum Analyzer. The RSA306 has an RF bandwidth from 9kHz to 6.2GHz with a real-time analysis window of 40MHz. While being entirely powered form a single USB 3.0 interface, it provides a 100% Probably of Intercept for any signal event of at least 100us in duration. The RSA306 is compact, lightweight and shock resistant. At the same time Tektronix has made its Signal-Vu PC software with 17 measurement capabilities free and significantly reduced the price of other Signal-Vu advanced applications!
The SFDR, linearity, noise floor and phase noise of the instrument are all measured and presented. The unit is then used to capture and analyze an intermittent RF interference, analyze and demodulate an RF FM signal using an antenna as well as demodulation a 256-QAM signal with -65Bm of total power.
In this episode Shahriar reviews the new Keithley 2450 Source Measure Unit (SMU). This model, which is the successor to the widely adopted Keithley 2400, offers performance improvements as well as a brand new interface platform with multi-point touch screen.
The review demonstrated the instruments GUI, scripting capabilities through the TSP interface and various performance parameters. Furthermore the scripting features are used to measure super capacitor capacity, the performance of a wireless charging system, characterization of optoelectronic components and semiconductor elements.
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.
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