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Si5351 RF signal generator. #SI5351 #RF #Signal Generator #si5351 #rf #signal


ashok.das81@...
 

Hi all,

I was hoping to make a RF signal generator using SI5351. Similar projects already done as I found in internet.

https://kk9jef.wordpress.com/2017/07/10/si5351-signal-generator/
https://wb8nbs.wordpress.com/2018/01/04/arduino-si5351-powered-signal-generator/
https://www.instructables.com/id/Arduino-Frequency-Synthesiser-Using-160MHz-Si5351/

My question is SI5351 is a clock generator and it generated Square wave. I wanted to say that it doesn't generate a clean sine wave. If I try to do testing of RF circuits using this will not there be problem due to harmonics ? Will it be sufficient for testing of circuits for HF ? The testing is in my home lab and not in any professional environment. Or should I go for a sine wave generator like AD9850 ? I need your suggestion before start on this project.

Thanks & Regards
Ashok Das


Ashhar Farhan
 

You have to be careful of false responses. Let's imagine you are testing a bandpass filter at 6 mhz. As the si5351 sweeps from 1 mhz to 10 mhz, at 2mhz, the si5351's output will also contain 6 mhz harmonic and this will pass through the 6 mhz filter giving a false response that will lead you to believe that the filter is passing signal at 2 mhz as well.
- f

On Sun 10 May, 2020, 12:40 PM , <ashok.das81@...> wrote:
Hi all,

I was hoping to make a RF signal generator using SI5351. Similar projects already done as I found in internet.

https://kk9jef.wordpress.com/2017/07/10/si5351-signal-generator/
https://wb8nbs.wordpress.com/2018/01/04/arduino-si5351-powered-signal-generator/
https://www.instructables.com/id/Arduino-Frequency-Synthesiser-Using-160MHz-Si5351/

My question is SI5351 is a clock generator and it generated Square wave. I wanted to say that it doesn't generate a clean sine wave. If I try to do testing of RF circuits using this will not there be problem due to harmonics ? Will it be sufficient for testing of circuits for HF ? The testing is in my home lab and not in any professional environment. Or should I go for a sine wave generator like AD9850 ? I need your suggestion before start on this project.

Thanks & Regards
Ashok Das


ashok.das81@...
 

Thanks a lot Farhan,

I always liked your straight on the point replies. I got it.

Regards
Ashok Das


Tony W
 

I think the results would be too confusing if used as a signal generator. I use one here as an analogue vfo replacement, but I used a low pass filter on the output so I get the same sine wave out of it as I do on the old analogue vfo. I think that is the only way to use it as a sig gen.
Regards
Tony, G4CIZ


Ashhar Farhan
 

Well, if you know to expect it, you can ignore it. No test instrument is perfect and truthful all work with limitations. To circumvent the harmonic problems, I built the Antuino. 
- f

On Sun 10 May, 2020, 8:24 PM Tony W via groups.io, <zeldone=yahoo.co.uk@groups.io> wrote:
I think the results would be too confusing if used as a signal generator. I use one here as an analogue vfo replacement, but I used a low pass filter on the output so I get the same sine wave out of it as I do on the old analogue vfo. I think that is the only way to use it as a sig gen.
Regards
Tony, G4CIZ


Arv Evans
 

On most signal generators the sine wave only survives until you connect it 
to something.  Maybe a receiver input would retain the sine wave, but if the 
signal generator is driving a diode that would distort the wave shape.  If the 
impedance is not perfectly matched, that would distort the wave shape.  

The answer really is "maybe" and depends on what you want to use it for.
Knowledge of what you have and what you want to get from it is required 
for signal generators, oscilloscopes, voltmeters, and other test equipment.

Arv  K7HKL
_._



On Sun, May 10, 2020 at 9:48 AM Ashhar Farhan <farhanbox@...> wrote:
Well, if you know to expect it, you can ignore it. No test instrument is perfect and truthful all work with limitations. To circumvent the harmonic problems, I built the Antuino. 
- f

On Sun 10 May, 2020, 8:24 PM Tony W via groups.io, <zeldone=yahoo.co.uk@groups.io> wrote:
I think the results would be too confusing if used as a signal generator. I use one here as an analogue vfo replacement, but I used a low pass filter on the output so I get the same sine wave out of it as I do on the old analogue vfo. I think that is the only way to use it as a sig gen.
Regards
Tony, G4CIZ


GM4CID
 

The AD9833 set to givea a sine wave output might be a better choice but is limited to 12.5MHz.

Bob GM4CID


ashok.das81@...
 

Thanks to all for your valuable feedback.
I am going with SI5351 for now as I have it with me. I will be careful during measurements. This is only option left now as not possible to acquire AD98XX devices due to lockdown.

Regards
Ashok Das


 

Ashok,

I just got a postal delivery of some parts ordered a few months ago. This means you can order.

Raj

At 11/05/2020, you wrote:
Thanks to all for your valuable feedback.
I am going with SI5351 for now as I have it with me. I will be careful during measurements. This is only option left now as not possible to acquire AD98XX devices due to lockdown.

Regards
Ashok Das


MVS Sarma
 

Ashok jee i have ad9850 modules 3 row version . I can send if you want.

I am located at hyderabad.
Regards
sarma vu3zmv 

On Mon, 11 May 2020, 2:29 pm Raj vu2zap, <rajendrakumargg@...> wrote:
Ashok,

I just got a postal delivery of some parts ordered a few months ago. This means you can order.

Raj

At 11/05/2020, you wrote:
>Thanks to all for your valuable feedback.
>I am going with SI5351 for now as I have it with me. I will be careful during measurements. This is only option left now as not possible to acquire AD98XX devices due to lockdown.
>
>Regards
>Ashok Das