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While I was doing my Analog Filter Design (ELE430) class at Ecole de technologie supérieure, we had to use the Agilent/HP 4195A Network/Spectrum Analyzer in the lab to plot filter frequency responses. One problem I encountered was that the GPIB slave on it was a Centronics (parallel-port printer) adapter connected to a LaserJet printer, which meant we could not directly access the data internal to the instrument. We could only plot it on paper.
To solve this problem and get access to the full 400 points of data memory for each HP4195A channel, I wrote the DL4195A utility (which stands “DownLoad 4195A”). The program requires a Prologix GPIB-USB Controller to connect to the instrument. This GPIB-USB adapter appears as a virtual COM Port and supports all GPIB bus operations. I strongly recommend it. The program is written in Python and uses the PySerial library.
The program has the following features:
- Downloads both internal registers (A and B) from the HP4195A
- Supports all HP4195A Network and Spectrum modes
- Outputs data as a TSV (tab-separated text file) compatible with Excel
- Output file uses same headings as a HP4195A Hardcopy
- Data is available with full instrument precision
- Auto-detects available serial ports (COM1-COM128)
- Does NOT affect measurement setup