Veronica PLL

[MNA]

what is PLL???...what have to be done to make the circuit without PLL???...

 

[ante1]

Hi MNA,

I was not able to open your link; can you please check if it’s valid?

 

[awright1]

Well, the link opened for me, but the schematic there is impossible to read unexpanded and if you expand it you can only see a small portion of the schematic, making it difficult to read

 

[MNA]

Hi awright, below is the link where u can find the veronica 1 watt PLL FM transmitter....Sorry for not supplying it before...but I thought u can find it by the schematic link....
http://gbppr.trighost.org/lpfm/index.html

I heard Sasi talking about this crkt without PLL section http://www.electronics-lab.com/forum/index.php?topic=4034.0 ....That's why I asked what i have to do to remove it....and also I don't understand why the crkt is so complicated...Is this because of PLL???

Why am I trying to remove it? well the answer is I'm not...actually I was just trying to discover that if the crkt complication is due to the PLL section?...can you tell me something about the crkt or it's block diagram...I'm relatively new to the subject..
Thanx

 

[ante1]

http://gbppr.trighost.org/lpfm/index.html

“You are not authorized to view this page”

None of these links works for me!?  :-\

 

[MNA]

Hi Ante,
I don't know what's the problem...I tried to attach it....but got the message that the upload folder is full....???????

 

[audioguru2]

I posted a new topic about the "Upload Folder is Full" problem.

The Veronica FM transmitter without the PLL is not legal to use in Britain, because its RF frequency drifts all over the place.
Look in Google at Phase-Locked-Loop and you will see that it has an accurate crystal oscillator, a counter and a detector circuit that locks the RF carrier to a multiple of the crystal's frequency.
The Veronica circuit is pretty old. Now there are ICs that perform most PLL or frequency-synthesizer functions simply.

 

[MNA]

I searched for PLL fm trans ....But found PIC's in all....Is there any other way out?I don't know about PICs.

 

[MNA]

Hi,Ante
that link worked or not??
I've attached the crkt.

Veronica_schematics.zip

Veronica_construction.zip

 

[audioguru2]

Silicon Chip magazine has an FM stereo transmitter project called Micromitter that uses Rohm's modern IC that has a very accurate PLL. The IC is inexpensive and is available at many suppliers.

The project operates very well and is much smaller than an old Veronica.

View attachment 38922

 

[MNA]

Veronica doesn't hav pre -emphasis.....Why?? Is this not going to do any harm?

Audio,I've seen that project and read your views on that...no doubt it is good...but I want to understand why Veronica is not good....

 

[audioguru2]

FM radios have de-emphasis which is treble cut. Since the Veronica transmitter doesn't have pre-emphasis to match it then it will sound something like an AM radio or like your stereo with its treble control turned all the way down. Not good.

 

[awright1]

But, Audioguru, isn't the pre-emphasis just a simple RC network that could easily be added to the Veronica?

awright

 

[audioguru2]

But, Audioguru, isn't the pre-emphasis just a simple RC network that could easily be added to the Veronica?

If the Veronica transmitter has enough gain.
If the Veronica is not stereo, because the boosted high audio frequencies need to have sharp lowpass filters to avoid having the 19kHz pilot signal and the 38kHz stereo sidebands from being messed-up.

 

[awright1]

Oh.  Thanks for the info.

awright

 

[MNA]

Hi Audio,I just read the  specifications of Veronica PLL (this is attached) and it says that
Pre-emphasis: none or 50 uS
also there is written
"If the 1 watt PLL is tobe connected with the veronica limiter compressor or stereo coder then pre-emphasis is not req. .To disable pre-emphasis remove C2 from the PCB."
I also read in an article 
"Pre and Deemphasis networks are characterised by their time constant. In the USA the standard is 75 uS, but in UK it is 50 uS so anything designed or bought from there needs slight modification. In a mono TX the pre-emphasis network can be built into the front end of the exciter. For a stereo TX such a network must NOT be in the exciter or it'll play hell with the composite stereo signal from the encoder. Instead you need two networks, one for each channel, on the inputs of the stereo encoder, They're actually often built into the stereo encoder"

from this the pre-emphasis looks ok...but the review says that no pre-emphasis is provided  http://www.irational.org/sic/radio/veronica-1w.html ....why? u also said there is no pre-emphasis...is the crkt wrong ?

I got a Veronica 1 watt schematic without pll http://www.geocities.com/Area51/Nebula/3736/veronica.htm#tuning ......so is that review referencing this crkt???or both the crkts don't contain pre-emphasis??Plz make it clear...

View attachment 38935

 

[audioguru2]

There are a few Veronica 1W FM transmitter circuits.
The 1st one you posted is the PLL version and might have a little amount of pre-emphasis.
The last one you posted has none, and the articles say to use their "professional limiter compressor" or their "stereo coder" circuit that has pre-emphasis and lowpass filters.

 

[MNA]

Wanted to know your views on FRB fm transmitter attached below..... I want to try one of them(FRB or Veronica with PLL)....which one will u suggest me and why?? I think FRB is better (Veronica has less pre-emphasis and involves more parts)  and involves less parts??

View attachment 38965

 

[audioguru2]

I haven't tried it and haven't read a comparison, but I think the FRB circuit is more modern than the Veronica PLL.