MMTTY Settings

The RTTY and Soundcard tabs of of WinWarbler's Configuration window provide control over the basic settings required to configure the MMTTY engine for RTTY operation. The MMTTY engine provides additional settings that govern

the pre-filter
- bandpass filter shape
- notch filter shape
- Least Mean Squares (LMS) filter parameters
the RTTY demodulator
- IIR, FIR, or PLL discriminator selection and filter shape
- Limit amplifier gain control and over-sampling
- Smoothing filter IIR or FIR and filter shape
- Automatic Frequency Control (AFC) parameters
- Automatic Threshold Control (ATC) parameters
the RTTY decoder
- Baudot Codeset
- baud rate, bit length, stop bits, parity
- majority logic
the RTTY modulator
- diddle parameters
- letters/figure shift parameters
- band-pass and low-pass filter shape
Sound Loopback

Configuring these settings is accomplished by clicking the MMTTY Setup button on the Configuration window's RTTY tab, which displays MMTTY's 6-tab Setup window; the settings adjustable via these tabs are fully described in the MMTTY help file; several of these settings are also described below.

Sound Loopback

Full duplex soundcards can simultaneously generate and monitor AFSK. While you're transmitting RTTY, the Sound loopback panel on the Setup window's Misc tab lets you exploit this ability by

displaying text decoded from your transmitted RTTY signal
displaying text decoded from an independently received RTTY signal (e.g. during Satellite operation)

When the Sound loopback panel is set to OFF, MMTTY's demodulator is inactive. As characters are transmitted, they are displayed in RTTY Receive pane:

When the Sound loopback panel is set to Int., the RTTY Receive pane displays transmitted characters decoded from your transmitted AFSK signal, providing confidence that the Modulator is working correctly:

When the Sound loopback panel is set to Ext. (SAT), the RTTY Receive pane displays characters decoded from whatever signal is connected to your soundcard input. This can be used, for example, to display the received "echo" from a satellite you're working: