Myriacat

<br> <br>

• Linux spectrum analyzer with VLF SDR
• up to 4K fullscreen, fluid realtime Display
• fast, intuitive, portable & lightweight<br>
• get newest myriacat here<br>

<br>

<br>

💡 use myriacat as spectrum analyzer for your music/youtube etc:<br> linux does not route the speaker-output back to programs, the easiest way is<br> to install pavucontrol, and set "monitor of built-in Audio" at the recording tab.<br>

<br> <details> <summary><b>FAQ:</b> _{^{<i>click to expand</i>}}</summary>

• minimum requirements:<br> Linux 64bit on AMD64 compatibles with Alsa audio, X11 and OpenGL (Mint, Ubuntu, Debian, Manjaro, ..)<br> for extended analysis outside the HiFi range, a 24bit/192kHz Soundcard is recommended.<br>

• configuration:<br> on exit, .myriaconf.txt with editable input devices is created.<br> available devices can be listed with arecord -l<br> only 24bit HW can be addressed directly, others will be only available under "default"<br>

• antenna for DX?<br> the common Realtek ALC887 (24bit/192Sps) audio Codec allows<br> source impedances up to 40KOhm on the ADC (mic input).<br> a cable to a metal Doorframe or Radiator is sufficient to see<br> 50KW Time signal stations 500 miles away.<br> preamplifiers and tuned Antennas are recommended for weak Signals.<br><br> 16bit USB Audio Dongles often need much lower impendance sources,<br> its not possible to receive weak Signals without LF preamplifiers.<br>

• change color of the spectrum<br> via colorcode in myriaconf.txt, or direct with <kbd>1</kbd>,<kbd>2</kbd>,<kbd>3</kbd> and <kbd>q</kbd>,<kbd>w</kbd>,<kbd>e</kbd><br>

• playback of a 192ksps audiofile is cutoff at 22kHz<br> some distributions are capped at 22kHz audio for playback.<br> for audiophiles, specific HiFi/ HiEnd tests or other interests, those settings can be changed.<br> this is for Mint/Ubuntu with Pulseaudio. other distros might work different.<br> do this on your own risk! - audio hardware is usually only designed for 20Hz - 20kHz.<br> it is not advised to use this configuration permanently.<br><br> cat /proc/asound/card0/pcm0p/sub0/hw_params usually shows "rate 44100"<br> nano /etc/pulse/daemon.conf remove the ";" in front of "; default-sample-rate = 192000"<br> pulseaudio -k && sudo alsa force-reload to restart the driver and sound subsystem<br> cat /proc/asound/card0/pcm0p/sub0/hw_params will show "rate 192000" now<br><br> play software generated 96kHz_sine.wav (192kSps, 0 - 96kHz sweep, 16bit, 10 seconds, low volume)<br> set myriacat to linear mode (music button off), 192k, L+R, and realtime.<br> best viewed with initial window-size (1024 pixel) and 2*zoom factor (2048 FFT size).<br><br> its generally not useful to use this settings.<br> myriacat talks directly to the low level alsa hardware interface and can use<br> 192kSps from the HW input anytime, regardless of pulseaudio-configurations.<br><br>

</details> <details> <summary><b>applications:</b> _{^{<i>click to expand</i>}}</summary>

• logarithmic audio view:<br> essential precision tool for recording, mixing and mastering<br> real time monitoring for video streaming, live events and recording Studios<br> audio FX visualizer for DJ's and Professional Audio Engineering<br> visual feedback for vocalists and content creators<br> evaluate harmonics, frequency response curves, acoustic characteristics measurements<br> instrument tuning, note training, vocal aid<br> lossy compression quality analysis<br> hydroacoustics, whalesounds, aquatic studies and marine sound visualization<br>

• linear view:<br> pixelexact linear visualization of analog signals for scientific research<br> ham radio, panadapter, ripple control, DCF77, smartmeter<br> naval/submarine communications, alpha navigation, aviation beacons<br> wideband and narrowband sonogram, passive sonar, signal hunting<br> radio astronomy, SID monitor, lightning detector, whistlers, spherics<br> seismic logging, schumann resonances<br> forensic analysis, pattern detection<br> bioresonance feedback<br>

• upper sideband demodulator:<br> downconvert and listen to selected bandwidths from 270 millihertz to full 96kHz<br> LF continuous wave and communications receiver<br> VLF SDR, Grimeton Radio SAQ receiver<br> ultrasonic, infrasound, sonar and sonography converter<br> bat detector<br>

• oscilloscope<br> check for signal integrity and continuity<br> catch clipping, offset and distortions<br>

• vectorscope, goniometer<br> polar view of stereo image width and position<br>

• phase correlation meter<br> mono compatibility of the stereo signal<br>

• cepstrum:<br> inspection of motors and gearboxes,<br> acoustic signature vessel identification,<br> DEMON (Detection of Envelope Modulation on Noise),<br> speaker detection<br><br>

</details> <details> <summary><b>features:</b> _{^{<i>click to expand</i>}}</summary><br>

• designed and written in C, with low level ALSA and OpenGL access
• multithreaded in-house DSP kernel, without external libraries
• complex Fourier Transformation, DIT, inplace, radix2, based on Cooley Tukey
• FFT window size from 1024 to 262144 samples
• samplerate from 275sps to 192kSps, 24bit
• powerspectrum resolution up to 1 millihertz
• demodulator bandwidth from sub 1Hz to full bandwidth
• window size from 256*160 pixels to 4K fullscreen
• waterfall logging up to >100 years with scroll time display
• measuring ruler & harmonic series markers
• overlap-add FFT convolution filter for sideband demodulator
• vertical flank steepness (brickwall) filter without phaseshift
• A-weighting filter according to international standard IEC 61672:2003
• hidden bin processing in log-view, no missing data
• smart buttons replace options and setting-screens, no invalid parameters possible
• single volume control for the whole signaltrain
• every configuration is seamlessly changeable on-the-fly
• savestate memorizes all settings for next use<br><br>

</details> <details> <summary><b>changelog:</b> _{^{<i>click to expand</i>}}</summary>

• v1.2<br> extended long time measurements up to >100 Years<br> reversed average selector<br> updated colors<br> minimal visual changes<br> enforce max screensize of 4096*2048<br>

• v1.1<br> adapt main spectrum shading to new mesa driver specification<br> change goniometer presentation to fix software rendering bug<br> convert ruler seconds to timestamp<br> update font spacing<br> adjusted colors<br> tested on:<br> Mint cinnamon 18.3 - 20.1,<br> Ubuntu Gnome 20.10,<br> Debian KDE Plasma 10.7.0 and<br> Manjaro xfce 20.2.1<br>

• v1.0<br> first public release<br><br>

</details><br>

<b>license</b><br> See the LICENSE file for details <img align="right" width="128" src="../main/resources/logo_with_sign.png"> <br>

<b>feed the cat</b><br> Litecoin LTC: LaCh6jieaHP14D2VD36voiq4urkzaHZjGr<br>