In this episode Shahriar takes a close look at the FLIR MR160 Thermal Imaging and Moisture Meter. Featuring Infrared Guided Measurement (IGM) technology powered by a FLIR Lepton® thermal imaging sensor, MR160 helps you quickly see temperature patterns that point to potential hidden moisture so you know right where to place the meter probe to capture accurate readings.

After an overview of the camera functions a full teardown of the instrument is presented. The FLIR MR160 is based on a single PIC32 processor with built-in capacitance measurement capability. The MR160 is then used to detect a moisture spot on a floor tiling. The presence of moisture is then verified with both the pin-less and pin-based moisture measurement capability of the MR160. Finally, the MR160 is also used to measure temperature variation across a bank of resistors.

The Signal Path
http://www.TheSignalPath.com

In this episode Shahriar reviews the Keysight EXA Signal Analyzer / Spectrum Analyzer (N9010A). The X-Series Signal Analyzers and Spectrum analyzers from Keysight are compared against each other. The EXA is a general purpose spectrum analyzer with extensive applications.

The full instrument block diagram is presented with focus on various signal paths and frequency planning. Several of internal modules (RF Front-End, Digital Baseband Processor and LO Synthesizer) are also presented and compared with the block diagram. In order to examine the instrument's capabilities in a real-world situation, a complete superheterodyne wireless transceiver with a sliding-IF receiver is design and examined. Each individual component in the system (LNA, mixer, PLL, etc.) are individually characterized by using the EXA Signal Analyzer. The complete system measurements are also presented.

Various chapters in the video can be found at the following time marks:

Introduction (0:08)
Model comparison (0:50)
Instrument block diagram (4:27)
Module teardown and examination (20:39)
Instrument front/back panel (37:05)
Measurement setup description (43:22)
Doubler characterization with EXG as tracking generator (45:31)
LNA and mixer with Noise Figure personality and gain (57:31)
Signal Hound VSG25A I/Q modulator with OBW, ACPR, TOI (1:08:57)
PLL characterization with Phase Noise personality (1:19:49)
Full transmitter measurement with Keysight VSA (1:26:08)
Full wireless link characterization (1:30:28)
Concluding remarks (1:37:21)

The Signal Path
http://www.TheSignalPath.com

In this episode, Shahriar and Shayan discuss the design and characterization of a deceptively simple CMOS inverter-based transimpedance amplifier. The the large and small signal behavior of the CMOS inverter is discussed and measured using the Keithley 2450 and 2460 source meters. The transient response is also measured using a Keysight MSO-S series oscilloscope.

The small signal gain of the circuit is calculated from small signal parameters which are extracted directly by measuring the devices I/V characteristics. The NMOS/PMOS devices used are from an ADL1105 quad-discrete transistor IC. Through the use of a shunt-shunt feedback, the CMOS amplifiers is converted to a transimpedance amplifier which is capable of amplifying the current from a photo-detector diode by a gain of 30kV/A. The feedback theory is used to calculate the gain of the amplifier. The slides for this tutorial can be downloaded from The Signal Path website.

The Signal Path
http://www.TheSignalPath.com

In this episode Shahriar explores the functionality of the popular ESP8266 SoC chip. This IC incorporates a full ISM radio as well as the physical/MAC layer for 802.11b/g/n network communication. Furthermore it includes a uC core for code execution making it a low-cost candidate for Internet of Thing applications. This video uses a Sparkfun Thing evaluation board which also includes a LiPo batter charger, voltage regular, flash memory and all the I/O pins which are accessible to the user. The block diagram of the ESP8266 is reviewed as well as the schematic of the complete Sparkfun Thing board.

By using an Arduino library and the iOS application, a cell phone and the ESP8266 can simultaneously communicate with a server running the IoT application and transfer data between the application and the module. In this demo various components such as NeoPixel (WS2812), OneWire temperature sensor and battery monitoring functionality are implemented. The code is available from The Signal Path website.

The Signal Path
http://www.TheSignalPath.com

In this episode Shahriar takes a close look at the top-of-the-line Rigol DSA875-TG 7.5GHz Spectrum Analyzer. This unit which, offers a built in tracking generator for the full frequency range, has a portable form-factor. I offers the following performance:

9 kHz to 7.5 GHz Frequency Range
Typical -161 dBm Displayed Average Noise Level normalized to 1 Hz
-98 dBc/Hz at 10 kHz offset Phase Noise
Total Amplitude Uncertainty better than 0.8 dB
10 Hz Minimum Resolution Bandwidth

The unit is tested against linearity specification as well as overload conditions. The phase noise of the unit is also verified with an external Keysight synthesizer. The instrument is used to measure OIP3, P1dB input and output matching of various amplifiers. The tracking generator is also used to measure gain and switching behavior of a WiFi extender module. The built-in functions are used to measure OBW, channel power, ACP and THD. The teardown of the unit is also presented showing excellent build quality and manufacturing.

The Signal Path
http://www.TheSignalPath.com