SINUS RDS PROJECT

[sinus trouble]

Whilst not apparent in the image above? There are harmonics below the 57Khz Pilot!

As we zoom in, Spurs are also detected @ 24.4Khz and around 8Khz too!

Which i suspect these are the culprits for the "Audio Noise" that XXL is experiencing?

Image Below!

[sinus trouble]

RDS Spectrum2.PNG

[sinus trouble]

Also!

Just out of curiosity, I plugged the RDS directly to the LINE IN on my Mixer and pushed the volume to MAX!

Sadly all i got was......... Nothing?

So i switched to the PHONO IN (Amplified turntable input) and repeated the same! I did manage to get the "Burbles"

However, A bit underwhelming to say the least?!

[radium98]

then adding a high pass filter to remove attenuate theses harmonics is posible.

[XXL]

I’ll do a video of my rds encoder soon and show you. I have your design and my own which is more compact.

[sinus trouble]

then adding a high pass filter to remove attenuate theses harmonics is posible.

Yes indeed!

If kept separated from your Audio, I see no reason why it would not work!

[sinus trouble]

I’ll do a video of my rds encoder soon and show you. I have your design and my own which is more compact.

That would be interesting to see!

[obdbeats]

Here are the Gerber Files!

Gerber SINUSRDS PCB.zip

HI Sinus, are this Gerber files are "USB-friendly" with the PL2303?
another question, can Magic RDS or EasyRDS software be used to update info via textfile?

[sinus trouble]

Here are the Gerber Files!

Gerber SINUSRDS PCB.zip

HI Sinus, are this Gerber files are "USB-friendly" with the PL2303?
another question, can Magic RDS or EasyRDS software be used to update info via textfile?

Hello Obdbeats!

The Gerber File has a single +V Data pin and ground can be sourced anywhere on the PCB!

You can add whatever sockets work for you?

Some others on this forum have used USB successfully to program the radio text? However it seems to be a "Hit N Miss" exercise?

COM Ports direct from PC work everytime!

I have not tested the software you mentioned? The +Data pin is pretty robust and will not result in any damage if you wish to give other options a try?

[obdbeats]

Hi Sinus!! here is the "Rds Software" i use with MRDS1322 it have the capability of updating data from a txtfile "tinyRds" if you like to give a try.
https://www.mediafire.com/file/hb1q69ru ... 6.zip/file

Here are the Gerber Files!

Gerber SINUSRDS PCB.zip

HI Sinus, are this Gerber files are "USB-friendly" with the PL2303?
another question, can Magic RDS or EasyRDS software be used to update info via textfile?

Hello Obdbeats!

The Gerber File has a single +V Data pin and ground can be sourced anywhere on the PCB!

You can add whatever sockets work for you?

Some others on this forum have used USB successfully to program the radio text? However it seems to be a "Hit N Miss" exercise?

COM Ports direct from PC work everytime!

I have not tested the software you mentioned? The +Data pin is pretty robust and will not result in any damage if you wish to give other options a try?

[rigmo]

can you check ?

[rigmo]

inductance Q question how to find right one?
AL0410ST-121K 120UH 0.796 70q 3.00R 185mA
AL0410ST-151K 150uH 0.796 70q 4.20R 175mA
AL0410ST-100K 10uH 7.96 80q 0.65R 500mA

or
CDRH74NP-150MC-B
ASDRH8D28-8D43

https://www.omnicalculator.com/physics/ ... lc-circuit

[Albert H]

Look at the value! The one you need is the 150µH one.

Basically, the 150µH in parallel with its associated capacitor resonates at ~57kHz. The ideal capacitor would be 52nF, but a 56nF (which is a standard value) will probably be close enough.

You could also use a 220µH (probably easier to find) in parallel with 35nF (made of a 27nF capacitor in parallel with an 8n2F capacitor) - again this will resonate at 57 kHz.

[rigmo]

Albet Inductance core tipe can be used ASDRH8D28-8D43 ? or AL0410ST-151K 150uH 0.796 70q 4.20R 175mA?
Now im understood this part with, thank you
capacitors are not in value., they could find the required value.. measure with a capaciometer 56nF 10% can be easy 51nf...

[Krakatoa]

In the end it is your choice, but a coil with a high Q means it is closer to an ideal inductance, so you can get more narrow filtering when put into resonance.
Another topic is "loaded Q" which has a direct relationship between bandwidth, inductor value, and in-circuit equivalent parallel impedance.
There are a whole set of formulas to help out there, but to cut it short, for a given circuit impedance the resonant tank sees, a lower inductance gives higher Q and narrower bandwidth.
You can verify it in a simple simulation in LtSpice.

[sinus trouble]

The actual ones i have used are Bourns type RLB0914-151KL

They are larger than your average axial inductor, but work pretty well!

[3metrejim]

A bit late to the party, here are some thoughts:

For synchronisation maybe the technique from the very first broadcast warehouse RDS will work - they used an (antique) MC1310 to lock onto the multiplex signal and phase lock the actual (crystal) oscillator of the PIC (the pic sent out a signal to lock to, you'd have to divide the 57kHz by three and use that. It used a varicap on the crystal load capacitor to pull at the frequency ever so slightly to get to phase lock.

I'm not sure about the single transistor chopper/mixer, just something about it looks off. The pic is sure to be fast enough to oversample the data stream, and looks like the 57kHz carrier is generated by an on board module so doesn't take any processing power.

Decent block diagram and a 57kHz active bandpass filter here:

https://www.radioeng.cz/fulltexts/2008/ ... 88_092.pdf

[radium98]

Nice catch 3m , but no pcb or schematic etc... by the way also it could be done by ne567

[3metrejim]

Did some hard old hard drive archaeology and dug up the scans of the original broadcast warehouse rds coder. Not so much use without firmware and it is around 24 years old, but shows how it was done (the sync). Sorry about the quality of the scans, they were kindly provided by Stephen Moss back in 2001 and I certainly wasn't going to moan - I was super lucky to get them in the first place.

Enjoy...

[radium98]

3metrejim Thank for valuable search