Stereo Coder for FM Transmiter

[folkeu]

Hi,
I search crystal of
   * 9,728 MHz
   * 7,296 MHz
   * 4,864 MHz
for make a codeur stereo.
Google, my friend, say me not link for that 
Thank

[sarah90]

http://www.imendit.com/item/9-728mhz-49s-2-pin-dip-the-20pf-passive-quartz-crystal-oscillator-resonance-10-6-yuan-18697568073.html

[Armageddon]

Hi,
I search crystal of
   * 9,728 MHz
   * 7,296 MHz
   * 4,864 MHz
for make a codeur stereo.
Google, my friend, say me not link for that 
Thank

Long ago I made one, somewhere I have the Eagle file. If you want I look it and give to you.

[folkeu]

Long ago I made one, somewhere I have the Eagle file. If you want I look it and give to you.

Hi Armageddon,
Yes, I want good.
Thanks

@sarah90 : Thank for your link because I have 2 schema with this value of quartz and now I can test it.

[Armageddon]

Hi Armageddon,
Yes, I want good.
Thanks

@sarah90 : Thank for your link because I have 2 schema with this value of quartz and now I can test it.

Ok, see atached file. I do not remember the value of the XT, it can be deduced. 
Use a bandpass filter to keep the first harmonic and obtain the 19KHz.
The higher frequency harmonics are filtered in the final stage. I do not remember it well designed long ago.
The power stage is over dimensioned in order to feed more parts.

[Zexy]

Hi friends,

I used to build a lot of FM equipments as hobby and as "paying bill job" in the past, so I have some experience.

 I will upload schematic now  and hex file (tonight for some easy solution for 19KHz pilot signal generation using some AVR MCU and ordinary 16MHz crystal. I can't post the whole schematic of this MPX generator, cause it is proprietary  #$%$  but I will help you with your questions if you have some...

https://docs.google.com/open?id=0B6-eRRWCEyaBUjJpLXV5RkJ3SU0

https://docs.google.com/open?id=0B6-eRRWCEyaBZFVIcmg2WVhvQTg

[folkeu]

Hi Zexy,
Thank you for your help but I know not write a program for a µ-controler.
I use as example a schema of a RVR stéreo codeur, an other one of a pilot FM and TDSS2 of AEV.
There is 19 and 38Khz make by a crystal. There too other frequency multiplier of 19Khz  304, 608 KHz ans other one in my memory) for 4 CD4066.
I search a crystal of 9,728MHz for tested this différent codeur and make one after with my schematic.

[DreamCat]

@Zexy, the resistor network use in R-2R network is a good idea, but I have never tried it.
Dos it have sufficiently high accuracy?

@folkeu, the 38kHz crystal may not easy to get, related frequncy crystal is too. unless you can only use it.

[bobcat1]

Hi All

You can use a lowcost module from dealexterrm.com as the hart of an hq fm transmitter
see the link below

http://dx.com/p/vmr6512-hi-fi-fm-transmitter-diy-module-44121

Today I think the best way to create an FM stereo signal by using DSP technic
I do belive that the new STM32F3 can make stereo signal modulator fast and easy

If you are interested in how to - there was some old application not for blackfin processor (analog site) on how to create a digital fm modulator
in the old day only a balckfin DSP processor can do that - but today the STM32 can do it as well

All the best

Bobi


 

[ehnonymouse]

People like Quartslab will make crystals to your specification.

[Zorktronics]

  Hi folkeu, you didn't saw much about your project, if you are really thinking about making a transmitter, i can't see any advantage by doing this circuit with analog ic's, it's much easier and even less expensive if you are doing a few units to do this circuit with a BH1415 or BA1404 FM transmitter IC's.

   These ic's have an stereo encoder, oscillator and, for the BH1415, the entire PLL unit for the carrier frequency, the crystal needed is one of the 38kHz frequency, it's cheap and easier to find than the crystals you are looking for.

[ehnonymouse]

I spent a long time looking for a 38kHz crystal for a BA1404 10 years ago with no luck, but I see there are some on ebay now #321069984964

[folkeu]

Hi,
I have finf a few part of quartz of 2.432MHz and I can try to make my codeur.
I have a schéma of an example (SSB FM30 Manual).
I have simuled the oscillateur with CD4060 (Proteus) and the value fréquencies are not in concordance with the sheet, the 4 at the bottom (WAL1, WAL3, /WAL1, /WAL3).
I'm not good in logic, Proteus bug or it's normal ?
Thanks

[h0nk]

Hi all,

i would recommend the MMR70 module, which is available at ebay.
This module contains an Alps-Transmitter and an ATMEGA32L.
Its completly programmable and able to do Stereoencoding and RDS.


Best Regards

[bobcat1]

Hi

Do it the easy way :

Use the ZL30250 fractional PLL clock generator ,can generate any clock from 9-25 MHz standard crystal


http://www.microsemi.com/products/timing-and-synchronization/clock-synthesis/zl30250-zl30251#docs-amp-specs



P.s. - this is a new chip ,you might find it hard to get in some part of the world.

All the best

Bobi