PSKmeter.py

PSKmeter.py is a display and analysis program for the PSKmeter station accessory. It is written in Python under Linux, but it should be portable to Windows or MacOS systems. It uses the Tkinter package for window management and display. If you wish to use PSKmeter.py, you will have to obtain the pyserial package for serial port I/O.

View or download pskmeter.py. [Rename the file, if necessary.] This is new and improved Version 0.25. This version is more tolerant of disconnecting and reconnecting the serial port or the power supply.

PSKmeter.py is copyrighted software. You may copy or adapt it freely for non-commercial applications. It may not be republished without permission.

Release Notes

dump screenshot Features

Full-cycle IMD analysis using "derectified" data.
Improved zero detection capability
ADC data are now linearized against a measured calibration function.
Controls soundcard PCM level - manual, not automatic
Provides optional raw data dump
Overload indicator

Known issues and areas for development

There is still some jitter in the waveform sync. This is mainly an esthetic problem. A complete cure would mean going to a 128 or 256 point interpolated data array.
Some improvements to the IMD / modulation quality index are possible, by choosing other statistics, by averaging over cycles, etc.
The PSKmeter is a great tuning aid, but it has limited dynamic range and it's not very linear. As such, I don't advise relying on its "IMD" numbers too much.
The calibration curve, overload limit, etc. are based on my particular unit. Your mileage may vary.
This program was developed using Python 2.2.3 under Fedora Linux FC1.
Because Python 2.2.3 does not have direct support for audio mixer control, PSKmeter.py 0.20 uses a piped process running 'aumix'. With Python 2.3, direct OSS audio support is available.
The audio mixer interface is Linux-specific, but should be adaptable to other platforms.

Your comments and suggestions are welcome -- to aa6e ...at... arrl.net.

Updated: 3/14/2004

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