In this episode Shahriar takes a close look at a defective Agilent E4440A spectrum analyzer. Initial analysis reveals that the startup errors are caused by a defective pre-amplifier module. During initial alignment and calibration, the defective microwave relays inside the pre-amplifier module fail insertion loss specifications and cause alignment failures.
Unfortunately, the relays are not repairable and must be replaced. Two new relays are purchased and replacement clears all alignment issues. The main motherboard battery has also failed; a replacement battery corrects any time and date keeping errors. The repaired instrument is cycled through several alignment procedures without any problems. The performance of the unit is verified by examining the DANL of the instrument with and without the pre-amplifier activated.
In this episode Shahriar takes a close look at the newly released Siglent SDG6000X Series Pulse / Arbitrary Waveform Generator. SDG6000X is a series of dual-channel Pulse/ Arbitrary Waveform Generators that feature up to 500MHz output frequency, a maximum sample rate of 2.4GSa/s and 16-bit vertical resolution when used as a function generator. The particular reviewed model is the SDG6052X which is the top-end model.
The full teardown of the unit reveals the internal architecture of the instrument, DAC / FPGA interconnect as well as the output amplifier structure. Although the limitations of the FPGA prevents the instrument to operate at full 2.5GSa/s in arb-mode, the instrument is capable of providing complex modulation up to the full 500MHz signal bandwidth.
This comprehensive review is organized as follows:
00:01:11 – Siglent SDG model overview and comparison
00:03:10 – Front and back panel overview
00:06:24 – Full teardown and analysis of the instrument archietecture
00:18:19 – GUI overview, menu structures and built-in functions
00:22:31 – Waveform phase and amplitude accuracy, characterizing a 180-degree hybrid
00:30:42 – Large-signal generation, ultra-sound experiment and range measurements
00:36:38 – Pulse generation performance, spectral content and low-pass filter measurements
00:44:07 – THD measurements, harmonic generation, Two-tone TOI measurements using waveform combine function
00:50:30 – PRBS pattern generator, ISI measurements and eye-diagram impairments using waveform combine functions
01:01:57 – I/Q modulation and waveform creation using EasyIQ as well as superheterodyne up-converter measurements
01:10:44 – Concluding remarks
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The 3458A unit fails startup conditions with several errors. After close inspection of the boards, the initial problem points to a poorly plugged in fiber-optic cable. After this fix, the unit still fails ACAL on the AC Board. The unit’s NVRAM modules all have to be replaced. During this process the memory of the unit is also upgraded and the firmware is updated to the latest available version. After analysis of the schematics the problem is traced to a damaged JFET input operational amplifier on the attenuator flatness calibrator unit. The replacement allows the unit to pass all self-test and ACAL calibration. The instrument is then NIST calibrated by AllTest Instruments and shows excellent performance when compared with various multimeters in the lab.
In this episode Shahriar reviews the newly released FPC1500 Spectrum Analyzer from Rohde & Schwarz. With this addition Rohde & Schwarz continues to aggressively target the entry level market across a wide range of instruments. These units are packed with competitive features some of which are not found in other instruments in the same class. The FPC1500 employs a 10.1″ WXGA LCD screes and a built-in tracking generator with a fully independent synthesizer which allows for offset tracking as well as a built-in VSWR bridge capable of making vector S11 measurements. These features combined with built-in WiFi, wide range of measurement capabilities and digital demodulation of ASK/FSK signals provides a competitive product.
This comprehensive review is organized as follows:
00:01:35 – R&S Spectrum Analyzer model overview
00:02:25 – Front and back panel, GUI initial look
00:06:24 – Complete teardown with digital and RF deck analysis
00:19:11 – DUT device overview and specifications
00:20:00 – DUT power on, FPC overload test, single tone, phase-noise and pre-amplifier performance
00:29:41 – TOI measurement capability and multi-tone inter-modulation performance
00:35:07 – Internal source performance, THD measurement, tracking generator and offset-tracking
00:41:55 – Scaler S21 configuration, DUT gain and bandwidth measurement
00:46:08 – DUT Noise-figure measurement and marker functions capability
00:48:57 – DUT variable gain control characterization, AM demodulation, VGA bandwidth and waveform display
00:57:39 – Digital demodulation of FSK/ASK with multilevel frequency shifting, eye-diagram display and analysis
01:01:13 – Vector S11 measurement, web interface, smith chart display and return loss characterization
01:04:45 – Spectrogram measurement, replay mode and trace storage
01:06:55 – Concluding remarks
The Signal Path (TSP) is an electrical engineering video blog for industry professionals, students and hobbyists. TSP is a non-for-profit website dedicated to provide free education spanning a wide range of electrical engineering topics. Equipment reviews, tutorials and repair videos are posted regularly.