Waterfall and tile data #2

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Here is my data:
Waterfall {streamId=0x42000000, bandwidth=0.016, centerFreq=18.0780006, size=1500,800}

WaterfallTile{FirstPixelFreq=18058301, BinBandwidth=11.0, LineDurationMS=80, _width=3360, _height=1, Timecode=5, AutoBlackLevel=11570, DateTime=Tue Jun 16 10:35:17 EDT 2015}


Waterfall {streamId=0x42000000, bandwidth=0.016, centerFreq=18.0780006, size=1500,800}

WaterfallTile{FirstPixelFreq=18058301, BinBandwidth=11.0, LineDurationMS=80, _width=3360, _height=1, Timecode=6, AutoBlackLevel=11570, DateTime=Tue Jun 16 10:35:17 EDT 2015}


Waterfall {streamId=0x42000000, bandwidth=0.016, centerFreq=18.0780006, size=1500,800}

WaterfallTile{FirstPixelFreq=18068150, BinBandwidth=5.0, LineDurationMS=80, _width=3360, _height=1, Timecode=7, AutoBlackLevel=12070, DateTime=Tue Jun 16 10:35:17 EDT 2015}


Waterfall {streamId=0x42000000, bandwidth=0.016, centerFreq=18.0780006, size=1500,800}

WaterfallTile{FirstPixelFreq=18068150, BinBandwidth=5.0, LineDurationMS=80, _width=3360, _height=1, Timecode=8, AutoBlackLevel=12070, DateTime=Tue Jun 16 10:35:18 EDT 2015}


Question 2) There was a post Steve made on the second page of Williams Android app thread, where he talked about waterfall stuff.
The first pixel in the batch of data is 18.0583 MHz yep got it
There are 3360 data points, the shorts shown above
Each datapoint represents 11 Hz.

I interpret this to  mean - the OnDataReceived event is sending data that starts at
18.0583MHz for 36.960KHz. As Steve pointed out, this data spans the pan window size to represent frequencies below that shown in the pan as well as frequencies above that shown in the pan. Am I interpreting this correctly to say the bandspread for that row of the waterfall goes from 18.0583 to 18.0952 MHz? The pan, goes from 18.070 to 18.086. This seems to support what Steve said the waterfall is wider than the pan. I am concluding therefore, that not only is my math correct so is the interpretation of the data headers. Correct?

Where my problem starts is interpreting that last tile and, worse, one from yesterday.
The last tile above would equate to representing a bandwidth from 18.068 to 18.084. This high end seems wrong as it is within the spread of the pan, on the upper side. If a subsequent packet had a starting pixel frequency of 18.085, I'd feel much better. However, the previous one has the same range so something seems to be incorrect. Would you weigh in on this please?

Yesterday, with the identical pan values I was getting tile values such as
WaterfallTile{FirstPixelFreq=17847188, BinBandwidth=187.0, LineDurationMS=40, _width=2460, _height=1, Timecode=4, AutoBlackLevel=0, DateTime=Mon Jun 15 20:06:55 EDT 2015}
Total bandwidth of waterfall line = 17.847 to 18.307 which seems completely...wrong?
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Walt - KZ1F

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Posted 3 years ago

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Stu Phillips - K6TU, Elmer

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Please see my post at 

https://community.flexradio.com/flexradio/topics/generating-a-pan-adaptor-and-waterfall-display

for calculating the frequency of incremental bins in the WaterfallTile.

To render the Waterfall, you need to retain a list of tiles that is at least as long as its height in pixels.

Each tile may have a different start frequency is you have caused the pan adaptor center frequency to change.

Each tile may have a different binBandwidth if you have changed the bandwidth of the pan adaptor.

Its up to you (the client) to figure this out and render the waterfall from the data you already have. This may require interpolation or chucking in the towel and starting to accumulate a new list of tiles rendering the bottom of the waterfall black until you have enough data.


Stu K6TU

PS: Don't forget the like... ;-)
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Jon - KF2E

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I'm going to like this even though I don't completely understand it. I think it is great that Stu donates his time to help developers here on the forum.

Jon...kf2e
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Walt - KZ1F

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@Stu, SMOP?

I am not a real big fan of the Waterfall. I think it has a near instantaneous value, but scrolling back and redrawing it, I don't know. However, just because I don't doesn't mean a customer of mine wont. The nice thing about what I am doing is if the framework sees a GPU, it'll dive into OpenGL or OpenGL-es. My framework will easily do 60fps, now that is high def.
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Walt - KZ1F

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@Jon, gee thanks.
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Jon - KF2E

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Walt,

I like what you are doing as well. I hope your project results in an IOS app that I can use to access my radio...keep at it:)

Jon...kf2e
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Walt - KZ1F

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As I've told Stu, running on an iPad required running the source thru a conversion program, do able but I haven't done it. Mac is out of the box.