Recent FSK chips?

Discussion in 'Wireless & RF Design' started by Ironic, Nov 29, 2011.

  1. Ironic

    Thread Starter Member

    Dec 23, 2008
    10
    0
    Hi guys.

    I am doing a project where i want to use FSK modulator and demodulator connected to microcontrolers (pic) for a radio link.

    I have XR 2206/XR 2211 and the LM567 tone decoder. They work but they are old chips, some versions even obsolete, and i would prefer to give a more modern look to the project. I've tried to look around for modern replacement's but no luck.

    Cristal controlled oscillators would be better for lower frequency drift versus temperature. Also if the frequency could be higher (at least 1Mhz) even better.

    Any ideias?

    Tks
     
  2. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Newer PICs have a Data Signal Modulation peripheral which can do FSK, PSK, and on/off keying.

    The 16F1827 has one for certain, as I just read that from Page 193 of the datasheet.
     
  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    I requested some 16F1827's and PIC16F1933's as samples - it took awhile for them to ship (they were very new at the time) but I got them a couple of months later. These things have more functions than you can shake a stick at.

    It's really amazing what functionality they are stuffing into the newer models.
     
  4. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    They only "common" PIC peripheral they left out of the 1827 was USB, but it only has 18 I/O pins, so it is forgivable. The amount of RAM and Flash storage are impressive, even for an "Enhanced Mid-Range" PIC as well.

    Yes, onboard peripherals are where AVR and PIC diverge rapidly. The Arduino OS uses a lot of bit banging to have abilities the hardware doesn't, such as PWM on any pin. At least the Arduino Uno 32 PIC can do a bit more without using up processor cycles.

    I predict it won't be long, if not already, that PICs with USB Host ability are released, so thumb drives or mice can be plugged into them for data or interfacing.
     
  5. AlexR

    Well-Known Member

    Jan 16, 2008
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    You don't say what sort of radio link you are going to use, distance, frequency, power etc but many off the shelf radio link modules have FSK/ASK features built-in. You just just provide the logic data (generally via some form of serial link, SPI,I2C or ASCII) and the radio module does the FSK mod/demod for you.
     
  6. Ironic

    Thread Starter Member

    Dec 23, 2008
    10
    0
    that seems like a really useful feature on the pic, however i need usb, so i can't change from the current 18F4550.

    Regarding specifications they are still open. The fsk chip i get will also dictate the type of transmitter used.

    The main question is that i have to use available transmitters so i have to do AFSK, meaning i have to shift the frequency of the transmitted signal and not the carrier. this is usually done with radio modems for frequencies in the hearing range but i want to go much higher than that.

    Can those radio link modules do that? Can you give an example?

    Like i said the XR 2206/XR 2211 pair and the LM567 do the trick, but i could do with more speed. any kind of chips that do at least the same at a faster speed would be good for me.

    Tks
     
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