Document the display values

[grahamwhaley]

We cover the display layout in the README, but we don't explain what the values of each entry mean. It would help users if we documented this better. Here is a very quick rundown for starters:

top line

When not in CW mode, the top line displays the current active settings slot (00-10), and the name of the slot (SSB etc, or Empty if the slot contains no settings.
When in CW mode, the decoded CW scrolls across the top line, from right to left.

Status line

The status line is always displayed, and the each status item/position has a fixed function. They are, in order from left to right:

Input volume

Shows 'bars' indicating the input signal volume level. A single '.' is the lowest level. Four 'bars' is a high level. If input clipping (volume too high) is detected then an ! will appear for 0.5s.

Bandpass filter

Indicates which bandpass filter is active. Values are:

• -> passthru (not actually off, but 'broadbanded')
• S SSB
• C CW
• A AM
• F FM

Noise blanker

Shows if the noise blanker is on or off. Shows - for off, and an 'impulse' type character (similar to ~ or a slanted N) when active.

Auto notch

Shows if the noise blaner is enabled or not. Shows - when it is off, and a stylised V when it is on.

AGC mode

Shows which, if any, AGC (like) method is in use. Values are:

• - Off (no AGC)
• T software 'tracking' mode (tries to match the peak output volume with the peak input volume)
• 5 SGTL5000 hardware AGC mode (the AGC in the audio codec hardware chip). Is not an AGC as you might think of it - there is not minimum level squelch type clip. Fundamentally it will try to maintain an even maximum volume without clipping.

Noise reduction

Shows which noise reduction algorithm is active. Values are:

• BYP complete bypass mode (may not be possible to configure currently)
• Off noise reduction is turned off
• LMS LMS reduction mode
• Kim Kim reduction mode
• fnr fnr reduction mode
• fnA fnrA reduction mode
• Spc Spectral reduction mode
• LLM LLMS reduction mode

CPU utilisation

Shows a rough estimate of the amount of CPU time that is being consumed doing the processing. Generally a fairly low number.

CW tuning aid

A rough guide to help tune in the CW decoder. The CW decoder 'listens' to the centre frequency defined for the active bandpass filter. The tuning aid listens for the 'loudest' tone in the signal, and shows one of five symbols to reflect how the detected tone relates to the bandpass:

• << Tone much too low
• < Tone too low
• x Tone matched
• > Tone too high
• >> Tone much too high

CW WPM

Shows the current detected CW word per minute speed as detected by the decoder that is active. Note, if using the Bayesian decoder there can be some delay between signals being heard and the WPM and decoded characters being printed.