Fluke PM6680B Frequency Counter 10MHz OCXO Reference Upgrade Module

OCXO Module

In this short episode Shahriar upgrades the recently repaired Fluke PM6680B with a new OCXO design by Dan Watson. The design of the module is examined as well various considerations for providing ultra clean 10MHz reference for instrumentation.  After module installation the unit functionality is verified. More information about the module is available here and here.

LCD Screen Backlight CCFL to LED Replacement

LED Backlight

In this short episode Shahriar demonstrated how to convert a CCFL backlight to an LED backlight on an Anritsu Network Analyzer. The construction of the existing LCD screen along with the new LED driver board are presented. The LED board provides an analog pin for brightness control. The final result is very impressive!

Teardown, Repair & Experiments with the Anritsu 37347A 20GHz Vector Network Analyzer

Anritsu _37347A

In this episode Shahriar repairs an Anritsu 37347A 20GHz Two-Port Network Analyzer. The unit does not boot up and as a result its internal state is unknown. The boot fault is traced to a bad RTC module which has a built-in integrated battery. A replacement unit is located which allows the unit to fully boot.

The instrument initially displays an unlock condition on the internal PLL. This problem is resolved by loading the PLL calibration files from the HDD. The complete block diagram of the unit is examined in detail and an unusual PLL intermittent locking problems is demonstrated. Various measurements on several of the internal PLLs confirm their functionality. As a final experiments, the instrument is calibrated and the S-parameters of a tune-able band-pass filter is measured.

Keysight N7020A 2.0GHz Power Rail Probe Review, Teardown and Experiments


In this episode Shahriar reviews the Keysight N7020A 2.0GHz Power Rail Probe. This power rail probe boasts the following features:

  • Low noise: 1:1 attenuation ratio probe adds only 10% to the baseline noise of the oscilloscope it is attached to.
  • Large offset range: Has a large +/-24 V offset range, enabling users to set their oscilloscope at maximum sensitivity and have the signal centered on the screen.
  • Low DC loading: 50 kΩ DC input impedance will not significantly load DC power rails.
  • Large active signal range: Has a +/-850 mV active signal range in addition to its large offset range so users can measure large transitions of their power rails.
  • High bandwidth: 2-GHz bandwidth makes it very useful for finding high-speed transients that can have detrimental effects on clocks and digital data.

After a brief presentation about the benefits of the N7020A, the probe and probe accessories are examined. The probe’s capability to provide up to +/-24V of offset is demonstrated and the input impedance at DC is measured. The probe is then used in conjunction with a Xilinx FPGA board to characterize a broadband power supply noise issue.

Tektronix TSG4106A RF Signal / Vector Generator Review, Teardown & Experiments


In this episode Shahriar presents a detailed review of the new Tektronix TSG4106A RF Signal / Vector Generator. The key features are:

  • True DC to 2 GHz, 4 GHz or 6 GHz to support both analog and vector/digital signal generation.
  • Typical ≤±0.30 dB amplitude accuracy (0 dBm CW signal at 22 ºC) from 10 MHz to 6 GHz.
  • I/Q modulation inputs (400 MHz RF bandwidth).
  • ASK, FSK, MSK, PSK, QAM, VSB, and custom I/Q.

A complete teardown of the unit is presented along with an explanation of various functions, components and sub-systems. The basic unit performance is verified using a Keysight EXA Signal Analyzer. The TSG4106A is then used to along with an Analog Devices I/Q de-modulator whose output is examined for performance verification.

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