Digital Data Transmission

Discussion in 'The Projects Forum' started by Skyferia, Mar 26, 2013.

  1. Skyferia

    Thread Starter New Member

    May 5, 2010
    20
    0
    [​IMG]

    Key
    01 - Altera DE2 Board (just assume it's an FPGA controlling 02 up to 15)
    02 - LCD Module (Hitach HD44780U)
    03 - PS/2 Port
    04 - N/A
    05 - Expansion Header 01 (40 ports; 1x +5V output; 1x +3.3V output; 2x GND; 36 I/O ports)
    06 - Expansion Header 02 (40 ports; 1x +5V output; 1x +3.3V output; 2x GND; 36 I/O ports)
    07 - PC Keyboard
    08 - DAC (component unknown)
    09 - Signal Generator
    10 - PCB (Transmitter board)
    11 - Transmitting antenna
    12 - Receiving antenna
    13 - Envelope Detector
    14 - ADC (component unknown)
    15 - LCD Module (Hitach HD44780U)
    16 - PCB (Transmitter board)

    • Basically when user keys in data using the PC keyboard (07), data is displayed on the LCD Module (02).
    • When the Return/Enter key on the PC Keyboard is pressed, data is sent to the DAC(08)
    • The output signal from the DAC (08) is sent through the transmitter(11) and received by the receiver(12).
    • Signal is asynchronous Amplitude Shift Keying (ASK) (ASK due to transmitting ASCII data bits, or is there a better option?)
    • The signal generator(09) inputs carrier signal. Frequency band is around 40~41 MHz.
    • The received signal is sent to the Envelope Detector (13) which demodulates the ASK signal.
    • The demodulated signal is passed through the ADC (14) and then the output data is sent to the LCD Module (15) to be displayed.
    • Transmitting distance doesn't matter, lets assume from 15 centimeters to 3 meters.

    Questions:
    1. Is/are there any mistake(s) in the design?
    2. If none for the above, what is a good DAC and ADC to use? An op-amp, perhaps?
    3. What is a good and inexpensive component/device for both the transmitter and receiver to use?
    4. For the envelope detector, is a diode detector a good option?
    5. Any idea on how to power up the transmitter & receiver boards? Using an external power supply, regulated with a voltage/switching regulator a good option?
     
    Last edited: Mar 26, 2013
  2. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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  3. Skyferia

    Thread Starter New Member

    May 5, 2010
    20
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    I see, thank you. Anything you would personally recommend, something inexpensive, yet efficient?


    That leaves with these questions:-
     
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