
Extra parts in my OCXO/Si5351A synthesizer module kit
#synth
#ocxo
#si5351a
Hi All There was a special run of 10MHz OCXO variants of the kit, at some point a couple of years ago. 100 were produced without Si5351A; and instead of the 27MHz crystal they had 10MHz, and 150pF cap
Hi All There was a special run of 10MHz OCXO variants of the kit, at some point a couple of years ago. 100 were produced without Si5351A; and instead of the 27MHz crystal they had 10MHz, and 150pF cap

By
Hans Summers
· #29983
·


Extra parts in my OCXO/Si5351A synthesizer module kit
#synth
#ocxo
#si5351a
well, that explains what I have in two ocxo kits that I purchased in July 2018. they both have these extra parts. the search here quickly supplied the answer! Thanks, Hans, for all that you do. 73, Ge
well, that explains what I have in two ocxo kits that I purchased in July 2018. they both have these extra parts. the search here quickly supplied the answer! Thanks, Hans, for all that you do. 73, Ge

By
George Byrkit
· #65334
·


Extra parts in my OCXO/Si5351A synthesizer module kit
#synth
#ocxo
#si5351a
I just finished a second OCXO kit and I freaked out when I found several leftover 151 caps (.15pf). When I looked at the parts list it didn't include these caps so they will go in my parts bin. Also t
I just finished a second OCXO kit and I freaked out when I found several leftover 151 caps (.15pf). When I looked at the parts list it didn't include these caps so they will go in my parts bin. Also t

By
...
· #29956
·


#synth ref frequency
#synth
Hi Alan, Did you ever figure out what the decode sensitivity to errors in the tone offset frequency is? I'm trying to scheme an inexpensive transmitter for WSPR on the 70 cm and maybe even the 33 cm b
Hi Alan, Did you ever figure out what the decode sensitivity to errors in the tone offset frequency is? I'm trying to scheme an inexpensive transmitter for WSPR on the 70 cm and maybe even the 33 cm b

By
HF
· #64569
·


#synth ref frequency
#synth
Hi all... The Si5351a datasheet says its reference frequency has to be 25 or 27 MHz. Others here have commented on using 26 and 10 MHz. What are the disadvantages of using other frequencies, other tha
Hi all... The Si5351a datasheet says its reference frequency has to be 25 or 27 MHz. Others here have commented on using 26 and 10 MHz. What are the disadvantages of using other frequencies, other tha

By
HF
· #64570
·


#u3s #synth 27MHz Crystal on Si5351 module failure? U3S just showing boxes...
#u3s
#synth
I've given the board a close review and there's not much I can tell with the board out of circuit. My oscilloscope (Tek T922) does show high frequency signal on the crystal pins so I'll assume it's os
I've given the board a close review and there's not much I can tell with the board out of circuit. My oscilloscope (Tek T922) does show high frequency signal on the crystal pins so I'll assume it's os

By
Al Holt
· #23124
·


use of the synthesizer module
#synth
In the ProgRoc the synthesizer is supplied 3.3vdc from the internal regulator as well as the 5vdc pull ups. So whether the synthesizer module has it's own 5vdc regulator is of no concern. In the vfo s
In the ProgRoc the synthesizer is supplied 3.3vdc from the internal regulator as well as the 5vdc pull ups. So whether the synthesizer module has it's own 5vdc regulator is of no concern. In the vfo s

By
Syd
· #76862
·


Request: Potential Mod for Si5351A Synthesizer Board
#progrock
#synth
Hans, This is a very lowpriority request, but it came to mind recently as I was playing with different TCXOs for the Si5351A Synthesizer Board. What is the possibility  on you next run of boards  o
Hans, This is a very lowpriority request, but it came to mind recently as I was playing with different TCXOs for the Si5351A Synthesizer Board. What is the possibility  on you next run of boards  o

By
Mike Besemer  WM4B
· #52729
·


#si5351a #synth #programming Si5351 programming: a deep dive
#si5351a
#synth
#programming
Order of operation is important here, at least if you are using integer math. Try this: P2 = (128 * b)  ((c * 128 * b) / c ) I am ignoring "floor" because that comes for free with integer division. N
Order of operation is important here, at least if you are using integer math. Try this: P2 = (128 * b)  ((c * 128 * b) / c ) I am ignoring "floor" because that comes for free with integer division. N

By
Paul WB6CXC
· #83708
·


#si5351a #synth #programming Si5351 programming: a deep dive
#si5351a
#synth
#programming
Some aspects of SiLabs AN619 appnote bother me regarding transforming "a+b/c" into P1, P2, P3 integer register values. As Hans has done, I'm calculating P1, P2, P3 for a fractionaldivider on the PLL
Some aspects of SiLabs AN619 appnote bother me regarding transforming "a+b/c" into P1, P2, P3 integer register values. As Hans has done, I'm calculating P1, P2, P3 for a fractionaldivider on the PLL

By
Glen Leinweber
· #83694
·


#si5351a #synth #programming Si5351 programming: a deep dive
#si5351a
#synth
#programming
This certainly is a curious equation. Neglecting the floor operator the answer is always zero. Perhaps this is a source of confusion. c or P3 is an integer. You need to pick a number. You shouldn't us
This certainly is a curious equation. Neglecting the floor operator the answer is always zero. Perhaps this is a source of confusion. c or P3 is an integer. You need to pick a number. You shouldn't us

By
Ron Carr
· #83701
·


#si5351a #synth #programming Si5351 programming: a deep dive
#si5351a
#synth
#programming
That should have been P2 = (128 * b)  (c * ((128 * b) / c) )  mathematically it's the same, but I guess when truncation occurs makes a difference
That should have been P2 = (128 * b)  (c * ((128 * b) / c) )  mathematically it's the same, but I guess when truncation occurs makes a difference

By
Paul WB6CXC
· #83710
·


#si5351a #synth #programming Si5351 programming: a deep dive
#si5351a
#synth
#programming
Certainly SiLabs intended this, which results in an unsigned integer whose range lies between 0127, hence their floor(128 * b/c) I wonder if you might help the compiler speed up the following calcula
Certainly SiLabs intended this, which results in an unsigned integer whose range lies between 0127, hence their floor(128 * b/c) I wonder if you might help the compiler speed up the following calcula

By
Glen Leinweber
· #83744
·


#si5351a #synth #programming Si5351 programming: a deep dive
#si5351a
#synth
#programming
Yes, exactly, and this is why we try to avoid floating point in speedcritical applications when using processors without FPUs.
Yes, exactly, and this is why we try to avoid floating point in speedcritical applications when using processors without FPUs.

By
Paul WB6CXC
· #83748
·


#si5351a #synth #programming Si5351 programming: a deep dive
#si5351a
#synth
#programming
I’ve been watching this discussion and I have to ask — is anybody watching the hierarchy of mathematical operations? This includes SiLabs. Unless otherwise defined by parentheses, multiplication and d
I’ve been watching this discussion and I have to ask — is anybody watching the hierarchy of mathematical operations? This includes SiLabs. Unless otherwise defined by parentheses, multiplication and d

By
Jim Strohm
· #83780
·


#si5351a #synth #programming Si5351 programming: a deep dive
#si5351a
#synth
#programming
Yes, singleprecision floats are dangerous, especially when calculating that nasty P2 that's giving me grief. recall that P2 requires multiplying "b" by 128, then subtracting (c * floor (128* b/c)). T
Yes, singleprecision floats are dangerous, especially when calculating that nasty P2 that's giving me grief. recall that P2 requires multiplying "b" by 128, then subtracting (c * floor (128* b/c)). T

By
Glen Leinweber
· #83806
·


#si5351a #synth #programming Si5351 programming: a deep dive
#si5351a
#synth
#programming
Glen, Aren’t you missing something? B and C are normally cast to floats before calculating B/C. Since B is less than or equal C, the ratio is less than or equal to 1. This is then multiplied by 128, r
Glen, Aren’t you missing something? B and C are normally cast to floats before calculating B/C. Since B is less than or equal C, the ratio is less than or equal to 1. This is then multiplied by 128, r

By
Milt
· #83807
·


#si5351a #synth #programming Si5351 programming: a deep dive
#si5351a
#synth
#programming
There is no need to cast these as floats. (128 x b) / c, using all integers and integer math gives you identical results. Yes, you can use floats if you like, and then, assuming enough floatingpoint
There is no need to cast these as floats. (128 x b) / c, using all integers and integer math gives you identical results. Yes, you can use floats if you like, and then, assuming enough floatingpoint

By
Paul WB6CXC
· #83818
·


#si5351a #synth #programming Si5351 programming: a deep dive
#si5351a
#synth
#programming
I've not seen the MDAS precedence problem in the SiLabs specs. I will sometimes overparenthesize my own equations to avoid integer overflow or to use truncation as required, or just to group things t
I've not seen the MDAS precedence problem in the SiLabs specs. I will sometimes overparenthesize my own equations to avoid integer overflow or to use truncation as required, or just to group things t

By
Paul WB6CXC
· #83781
·


#si5351a #synth #programming Si5351 programming: a deep dive
#si5351a
#synth
#programming
I keep mentioning Bresenham dividers. Here's a simple pseudocode example: Ratio = b / c counter = 0 loop forever { if (counter < 0) counter = counter + b else counter = counter + (cb) } And that's it
I keep mentioning Bresenham dividers. Here's a simple pseudocode example: Ratio = b / c counter = 0 loop forever { if (counter < 0) counter = counter + b else counter = counter + (cb) } And that's it

By
Paul WB6CXC
· #83782
·
