Archive for Equipment Review

Keithley 2450 Source Measure Unit (SMU) Review and Experiments

Keithley_2450

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.

Teardown, Analysis and Repair of an HP/Agilent 5347A 20GHz Frequency Counter & Power Meter

5347A

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.

Teardown, Analysis and Repair of an Agilent E4407B 26.5GHz ESA-E Spectrum Analyzer

E4407B

In this episode Shahriar takes a detailed look at an Agilent (Keysight) E4407B ESA-E Spectrum Analyzer. The instruments reports an “Unlock LO” error message which prevents internal alignments from being performed. Before the repair process can begin, the firmware of the instrument must be updated. The firmware upgrade requires the installation of additional flash memory ICs which is presented in the video. The main processor board with its various components are also described in the video.

The complete block diagram of the spectrum analyzer is presented with a detailed look at the principle of operation of the instrument. All the main functional blocks such as the YIG Oscillator, Phase Detector, LO Path, LO Amplifier, Charge Pump, Pre-tune segments, digital circuits, IF and LO paths are analyzed both in schematic and on the PCB. Several potential faults are investigated and measured.

Dino-Lite USB Digital Microscopes Review and Experiments

DinoLite

In this episode Shahriar takes a close look at some of Dino-Lite’s USB Digital Microscopes and accessories. Two of the microscope stand offerings from Dino-Lite are demoed (model MS36B and RK-10) with a close look at their features and usability. All USB stands offer precision Aluminum bodies and flexible ranges of motion for a variety of viewing angles and distances.

Three USB Digital Microscopes from Dino-Lite are also demoed: models AM4113ZTL Dino-Lite Premier, AM4515ZTL Dino-Lite Edge and AM4815ZTL Dino-Lite Edge. These microscopes offers features such as large magnification combined with long working distances, adjustable polarizer, adaptable cap design, MicroTouch shutter button, extended depth of field (EDOF), extended dynamic range (EDR) and automatic magnification reading (AMR) which are all compatible with the provide DinoCapture 2.0 interface software.

Using Dino-Lite’s microscopes, a variety of electronics components are presented: An Analog Devices PCB containing 0102 footprint components, A PIC UV erasable Silicon die, a 325GHz horn antenna, a composite wafer probe with 150um pitch from GGB industries. Finally, the complete breakdown of a QuinStar mm-wave PA module is shown with microwave filters, pre-amplifiers, and a Wilkinson-based GaAs PA as a final stage.

Tutorial on the Theory, Design and Characterization of Delta-Sigma Analog to Digital Converters

DeltaSigmaADC

In this episode Shahriar explores the world of Delta-Sigma modulators with emphasis on a Delta-Sigma Analog to Digital Converter (ADC). The basic concepts of analog to digital conversion is presented, particularly with respect to quantization noise spectral shape and power density. Next, oversampling ADCs are presented to demonstrate the possibility of increasing SQNR (ENOB) through manipulation of quantization noise spectrum.

Due to the practical limitations of high oversampling ratios, delta-sigma modulations is explored. The principle operation behind delta-sigma ADCs is presented with detailed explanation on noise shaping, filtering and decimation. The signal and noise transfer functions for a 1st order and 2nd order delta-sigma ADC are derived. Finally, as a practical example, a 2nd order delta-sigma ADC based on a 1-bit quantizer is presented. The ADC uses two Miller integrator op-amps, one comparator and a D-Type flip-flop. The complete measurement of this delta-sigma ADC is presented. The impact of over sampling ration, op-amp linearity and input signal bandwidth is presented. The slides for this video can be downloaded here.