Tag Archive for RF

Rohde & Schwarz 4.0GHz Portable Spectrum Rider FPH Review, Teardown & Experiments

In this episode Shahriar reviews the Rohde & Schwarz 4.0GHz Spectrum Rider FPH. The new design of the FPH series is aimed for ease of use in outdoor situations as well as offering several software features for data collection, analysis and debugging of standard wireless communication protocols. The review is organized as follows:

1:10 – Model comparison of R&S portable spectrum analyzers.
5:44 – Instrument hardware overview and GUI characteristics.
22:24 – Using the FPH Spectrum Rider to analyze unknown wireless signals including a multi-tone, QPSK modulated signal, AM/FM demodulation analysis and frequency hopping.
46:46 – FPH teardown and analysis.
55:33 – Overview of the Instrument View remote connection software.
57:42 – Concluding remarks.

Keysight MXA Revision-B Signal Analyzer / Spectrum Analyzer Review, Analysis & Experiments

In this episode Shahriar reviews the long awaited Keysight MXA Signal Analyzer (N9020B). The new X-Series Spectrum Analyzers from Keysight offer an entirely re-designed GUI interface which supports multiple tabs as well as multi-touch interaction. The review is organized as follows:

1:07 –   Model comparison and overview of x-series spectrum analyzers.
7:08 –   Instrument physical overview.
11:49 – New GUI overview and demonstrations.
22:44 – Instrument block diagrams and analysis.
28:46 – Brief look inside the MXA spectrum analyzer.
32:53 – Back-scattering communication experiment block diagram and description.
37:16 – Phase noise characterization of doubler and amplifier.
51:54 – Complete back-scattering experiment measurements and analysis.
1:04:45 – Analysis of broadband modulated signals by using the S-Series scope and MXA Signal analyzer at the same time.
1:13:56 – Concluding remarks.

Teardown & Analysis of Microwave (26.5GHz) Electro-Mechanical Step Attenuators

In this short episode Shahriar takes a close look at a pair of Hewlett Packard microwave electro-mechanical step attenuators operating up to 26.5GHz. Mechanical attenuators offer excellent repeatability, low insertion loss and nearly limitless linearity. The teardown reveals that the construction of both modules is very similar on the microwave path. In fact, the lower-frequency model still uses the same attenuator components. The newer model employs electronic control circuity while the older generation attenuator uses purely mechanically controlled DC path. Both models use a solenoid style actuators for step attenuation control.

Teardown, Repair and Experiments with a Tektronix RSA 6114A Real-Time Spectrum Analyzer

In this episode Shahriar attempts a difficult repair of a Tektronix RSA real-time spectrum analyzer. This well-equipped instrument reports several error messages during startup POST including LO Unlock as well as Signal Path failures. The service manual of the instrument does not provide any detailed block diagram and no schematics. Most failures require the instrument to be serviced by the Tektronix factory. The equipment has various advanced options including 110MHz analysis bandwidth, digital modulation analysis, wide-band IF output and deep memory.

The teardown of the instrument reveals a multi-board, multi-module design. The top of the instrument contains all digital blocks and boards while the bottom of the instrument houses the RF deck assembly. The RF deck is broken into various stages such as attenuator, RF switches, first converter, second converter, IF block, reference synthesizer and LO generator. For the purposes of addressing the YIG problems the LO board is examined. The problem is traced to two components, both dividers in the complex PLL system of the LO subsystem. The LO board is fully analyzed and described and the defective components re replaced.

The repaired instrument is tested for various functionality including DPX, de-modulation and measurement of beyond 8GHz CW tones. The instrument passes all self-tests, alignments and detailed diagnostics.

Tektronix MDO4104C-6 Mixed Domain Oscilloscope (MDO4000C) Review, Teardown and Experiments

In this episode Shahriar performs a full review on the Tektronix MDO4000C series mixed domain oscilloscope, particularly model MDO4104C-6. The MDO4000C combines up to six instruments including a function generator and a built-in spectrum analyzer. Unlike any other instrument, it can synchronize RF, analog and digital channels. These correlated measurements provide insight into difficult to find problems particularly intermittent events.

This review begins with a comparison between the MDO4000B and MDO4000C instruments. The full review of the MDO4000B can be viewed here. All experiments demonstrated in the MDO4000B review are also relevant to the MDO4000C instrument.

The teardown of the instrument reveals a multi-board construction where the ADCs, FPGAs, application processor and memory are on the main system board. A complete analysis of the entire system is presented including the operation of the RF module.

In order to demonstrate the instrument’s capabilities, an encrypted frequency hopping transmitter system is analyzed. The system exhibits various problems such as high BER, low SFDR, poor phase-noise and EVM. The MDO4000C is used to perform advanced measurements across analog, digital and RF domain to track and resolve these problem. The complete block diagram of the experiment can be found here.

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