ayeQ: A toolbox for working with IQ modulation

This project aims to create a command-line program that allows the creation of IQ modulated digital signals from different sources. These files can then be plaid back on SDRs or analyzed with other programs. Our goal is to make the generation of IQ signals easy for people using the command-line. We currently support the following kinds of modulation/synthesis:

• Amplitude Modulation (AM)
• Carrier Synthesis
• CW (Morse Code)
• Frequency Modulation (FM)

Amplitude modulation

The AM module takes an input sound files, applies AM to it, then interpolates the resulting IQ samples. The following options are allowed:

-i,--in-file INPUT_FILE  Input sound file
-o,--out-file OUTPUT_FILE
                         Output IQ file
-m,--modulation-index MOD_INDEX
                         Modulation index, value between 1-100 (default: 100)
-u,--upsample-factor UPSAMPLE_FAC
                         Upsample factor, outSR = inSR * UPSAMPLE_FAC
                         (default: 10)
-c,--cutoff-frequency CUTOFF_FREQ
                         Cutoff frequency, value in Hz (default: 15000)
-t,--transition-width TRANS_WIDTH
                         Transition width, value in Hz (default: 10000)
-h,--help                Show this help text

For example, suppose you wanted to apply AM to test.flac, with an interpolation factor of 15, you could use:

$ ayeQ am -i ~/test.flac -o ~/out.iq -u 15

Carrier Synthesis

Thie module generates a carrier at baseband for the requested length of time. The following options are allowed:

-l,--length LENGTH       Carrier length in seconds
-o,--out-file OUTPUT_FILE
                         Output IQ file
-s,--sample-rate SAMPLE_RATE
                         IQ Sample rate in Hz (default: 1000000)
-h,--help                Show this help text

For example, suppose you wanted to generate a baseband carrier for 10 seconds with at a sample rate of 1MHz:

$ ayeQ carrier -o ~/out.iq -l 10 -s 1000000

CW

This module allows IQ files to be generated that encode textual data with the standard more code. The following options are allowed:

-s,--sample-rate SAMPLE_RATE
                         Sample rate of the produced IQ file
-w,--wpm WPM_RATE        Rate of keying in Words per Minute (default: 25)
-t,--in-text INPUT_TEXT  Input text message
-o,--out-file OUTPUT_FILE
                         Output IQ file
-h,--help                Show this help text

For example, suppose you want to generate a CQ call at a sample rate of 600kHz:

$ ayeQ cw -o ~/cw.iq -s 600000 -t "cq cq cq de M0MLQ"

FM

This module allows IQ files to be generated that moduleate a sound file using frequency modulation. The following options are allowed:

-i,--in-file INPUT_FILE  Input sound file
-o,--out-file OUTPUT_FILE
                         Output IQ file
-d,--deviation-ratio DEV_RATIO
                         The raio of max_devation over max_mod_frequency.
                         (default: 1.0)
-u,--upsample-factor UPSAMPLE_FAC
                         Upsample factor, outSR = inSR * UPSAMPLE_FAC
                         (default: 10)
-c,--cutoff-frequency CUTOFF_FREQ
                         Cutoff frequency, value in Hz (default: 15000)
-t,--transition-width TRANS_WIDTH
                         Transition width, value in Hz (default: 10000)
-h,--help                Show this help text

For example, suppose you wanted to apply AM to test.flac, with an interpolation factor of 15 and a modulation ratio of 0.8, you could use:

$ ayeQ fm -i test.flac -u 15 -d 0.8 -o fm.iq