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Re: #uBITX Firmware KD8CEC - IF-Shift etc.
#ubitx
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Jerry and all Now I sit at my desk and have seen many opinions. I have not read all of them in too many emails, but I am so happy to have reached a good conclusion. I do not know if it's too late, but I'll tell you when I first implement the 'IF-Shift' feature for uBITX. As you may have guessed someone who viewed my source, the source for implementing Filter is not all of the sources I wrote above.? (I am sorry if you confused this with this.) I have a friend who has a lot of great ideas.?The friend told me to shift the IF passband to remove the ambient noise. And when I saw the circuit, I had to decide.? As you all know, uBITX has twice frequency mixing. It is using CLK # 2 and CLK # 1. CLK # 2 generates a reference frequency for passing the desired frequency through a filter composed of 45Mhz crystals. CLK # 1 generates a reference frequency for passing a filter composed of 12Mhz crystals. My simple idea is that the frequency control source created by jerry is very good and did not need to be modified much. Of course, CLOCK0 also makes the code look like it passes through the filter as shown below. I had to choose one of them to reduce ambient noise. and? decided to use a part made of 12Mhz crystals that look sharper.So I wrote the above code.? si5351bx_setfreq(0, usbCarrier + (isIFShift ? ifShiftValue : 0)); <--?This code is in the stopTX, Init parts for rx start. Yes, this is to shift the BFO. I thought about configuring it in the following form.?In this case, we did not have to worry about CLK0 throughout the code. ? ? ? si5351bx_setfreq(2, SECOND_OSC_USB - usbCarrier + f? + (isIFShift ? ifShiftValue : 0)); ? ? ? si5351bx_setfreq(1, SECOND_OSC_USB + (isIFShift ? ifShiftValue : 0)
); Or, I thought about processing options as below. (The code may be incorrect. Please consider it as a pseudo-code that you wrote during the writing of the mail now.) ? ? ? si5351bx_setfreq(2, SECOND_OSC_USB - usbCarrier + f?
+ (isIF1Shift ? if1ShiftValue : 0)
+ (isIF2Shift ? if2ShiftValue : 0)); ? ? ? si5351bx_setfreq(1, SECOND_OSC_USB +?(isIF1Shift ? if1ShiftValue : 0)?); si5351bx_setfreq(0, usbCarrier + (isIF2Shift ? if2ShiftValue : 0)); <--?This code is in the stopTX, Init parts for rx start. I wanted to give the user a tip to get rid of ambient noise for a while.?It was a short coding and in fact many tests were not done. By your opinion, this feature will be more advanced.
In addition.(The bottom part is my guess, so it may be wrong.
I was hesitant to write this because it was still an experiment.
) I think BFO Calibration is done by all users.?This is because uBITX can not be used if BFO calibration is not performed. However, there is no calibration for 45Mhz.?I thought maybe modifying the part that is constant might improve the reception ratio a little more. After implementing IF-Shift, I made several measurements through the Vector Network Analyzer. And we are doing simulation. If I continue to improve uBITX, I will share experimental results later. Thanks to Jerry's code, I was able to easily implement the functions I think very easily. Thank you for sharing this great code. Ian KD8CEC 2018-03-12 7:59 GMT+09:00 Tim Gorman <tgorman2@...>: Jerry, |
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