Editing Modulation Modes

The SimTX Transmitter supports the following modulation modes. The '''Auto''' bandwidth option fills the typical bandwidth for the selected mode; the bandwidth field accepts any value down to the mode's minimum.

{| class="wikitable"
! Mode !! Full name !! Typical bandwidth !! Minimum bandwidth !! Audio range
|-
| AM (full carrier) || Amplitude modulation, double sideband, full carrier || 10 kHz || 160 Hz || 80 to 4500 Hz
|-
| AM (suppressed carrier) || Double sideband, suppressed carrier || 6 kHz || 160 Hz || 100 to 2800 Hz
|-
| USB || Upper sideband || 2700 Hz || 300 Hz || 350 to 2700 Hz
|-
| LSB || Lower sideband || 2700 Hz || 300 Hz || 350 to 2700 Hz
|-
| CW || Continuous wave (Morse keying) || 150 Hz || 50 Hz || n/a
|-
| NFM || Narrowband FM || 12.5 kHz || 2.5 kHz || 200 to 3000 Hz
|-
| WFM || Wideband FM (broadcast) || 180 kHz || 50 kHz || 30 Hz to 15 kHz
|-
| IQ || External complex IQ input || 48 kHz || 100 Hz || n/a
|}

== Mode notes ==
* '''USB and LSB''' are suppressed-carrier modes. The carrier leak and opposite-sideband suppression settings in [[Advanced Transmitter Settings]] control how imperfect the suppression is. By convention LSB is used below 10 MHz and USB above, but SimTX does not enforce this.
* '''AM''' modes expose the AM modulation index setting. An index above 1.0 is overmodulation and produces audible distortion and splatter.
* '''CW''' exposes the key rise time setting. Very short rise times produce key clicks that widen the occupied bandwidth. CW is also the most sensitive mode: its narrow bandwidth lets it remain readable on paths where voice modes fail, see [[Propagation Basics]].
* '''NFM and WFM''' are constant-envelope modes; they are less affected by amplifier compression but need considerably more signal at the receiver than SSB. WFM supports stereo when fed from the PipeWire Stereo source.
* '''IQ''' passes externally generated complex baseband (for example from GNU Radio) straight to the channel. Selecting the GNU Radio IQ source forces this mode.

== Field interactions ==
* The low-cut field is editable for USB, LSB, both AM modes, NFM and WFM.
* Opposite-sideband suppression applies to USB and LSB only.
* Carrier leak applies to USB, LSB and suppressed-carrier AM.
* AM index applies to the two AM modes.
* CW rise time applies to CW only.
* PipeWire Stereo forces WFM; GNU Radio IQ forces IQ.

[[Category:SimTX]]