Pallette and colors

This is a section of the User's Manual, Chapter 4 -DSP-10 Software Setup

Screen and Waterfall Colors

The colors of the screen and waterfall are programmable from the configuration file . You first need to decide the 16 colors that you would like in your waterfall. There are 64 possible colors in the VGA system.

Put these 16 numbers into the configuration file, UHFA.CFG, (called cfg file below) using any text editor. The default entries look like:

palette 0 16 34 3 25 41 21 29 61 60 52 46 38 54 55 63

The left number is not used in the waterfall, and 0 is black. The next 15 colors are intended to be in order of increasing brightness. I make no claims that you will think the default ones are so arranged!. So feel free to change them. A couple of obvious problems: 60 and 52 are very similar; 46 and 38 are very similar. You get to view the colors for a short while, when you change either the contrast setting, or the brightness setting.

Now that you have done the best that you can with the waterfall colors, more likely than not, the rest of the screen will look pretty bad. The problem is that colors like the dark blue background are locked to palette member 4 (they are numbered 0 to 15, L to R), which is VGA color 25. You need to unlock this by picking one of the 16 palette members for the background and entering it into the cfg file as (lets say member 6):

  c_background 6

But you are not through. You need to pick a color from the palette for 14 more items. They define items like the present white text (c_text_bold) and the little red marker on the spectrum display c_plot_marker). The 15 items are not totally obvious, so a little playing will be needed. The 15 are, along with their default values:


Position	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
Palette	0	16	24	3	25	41	21	29	61	60	52	46	38	54	66	63

Variable	Position	Color		Uses
c_background	4	25	brt blue	Screen Background
Outline Colors
c_outline	11	46	orange	Outline and grid for upper spectral plot, horizontal lines for controls
c_outline_bold	15	63	white	Dialog box outlines outline of lower spectral box
c_outline_bright	8	61	lavender	Outline of ID and freq boxes
Text Colors
c_text	11	46	orange	Text in dialog boxes, freqs,secondary control values inactive dialog box text,"last key" text, Alt-A dialog box help text
c_text_bold	15	63	white	Control labels, Primary control values, A box text, Alt-B dialog box help text, upper spectral box scale numbers, "Receive" and "Transmit"
c_text_bright	13	54	brt yel	Active text in dialog boxes, text in freq box, scale label of yellow trace
c_text_note	9	60	red	Error msg, '*' for screen saves, "RECORDING" per ALT-F, Transverter name
Plot Colors
c_plot_bold	15	63	white	Upper spectral "white" trace, tick marks, vertical cursors
c_plot_bright	13	54	yel	Upper spectral "yellow" LT trace
c_plot_marker	9	60	red	Marker for "White" trace, Freq marker in slide rule dial
Bar Graph Colors
c_bar_dark	1	16	dk grn	All bars dark ALSO Waterfall background
c_bar_low	15	63	white	Bars 1-5
c_bar_medium	2	34	green	Bars 6-9
c_bar_high	9	60	red	Bars 10-15

In general, c_text is used for inactive (dimmed) controls or secondary settings, whereas c_text_bold is used for primary settings. The table above is not exhaustive, but shows enough items to allow colors to be reassigned without big surprises!

You can now have a customized color arrangement. If you like what you have come up with, please share it with the rest of us through the reflector. (dsp-10@qth.net)

Now, a couple of words on waterfalls. The eye along with the human brain obviously has excellent abilities to recognize patterns. The waterfall display provides these patterns, of course.

The problem with the DSP-10 waterfall is that it doesn't have very many colors, being constrained by the VGA. all right, maybe this will be overcome one of these days, but in the mean time, it is possible to do some very interesting work with the waterfall, just as it is. The reason is an effect called "dithering." If we are observing a noisy signal with a small number of quantized levels (our colors) this can have a similar effect to having many levels and a less noisy signal. In some cases dither noise is added to systems lacking in quantizing levels. In our case, the dither is a characteristic of the signal we are working with so we don't need to add it.

So how do you take maximum advantage of the dither effect. First, make sure the noise is fully onto the upper display area. If you cut off the low levels on the bottom you are tossing out useful dithered data. Next make sure that the contrast and db/div are set so that several colors are being used on noise alone--probably 4 or 5 is OK. Next, use the normalization to keep the noise line straight. If you are working with very weak signals, where Spec_ave of 30 or more is appropriate, you will want to use the precision normalization (Alt P or p) not the quick 10 second one (AltQ or q).

Play with it and then, move away from the screen and look for patterns. The present system works quite well on signals 25 dB below audible levels (in the -170 to -175 dBm range) with some playing.

I hope this is helpful. Let us know what your success is on this. Remember that all this applies to the audio processor, if you don't have working rf hardware yet.

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