NCD-1 NON-COHERENT ASK/FSK DEMODULATOR

The Type NCD-1 is a classical textbook representation of non-coherent demodulation of bandpass-filtered, envelope-detected ASK and MARK/SPACE FSK in the presence of additive noise. The envelope-detected ASK and FSK (MARK/SPACE) is compared to a variable threshold or the FSK MARK and SPACE can be compared to each other, to determine the bit sent. The Type NCD-1 demodulator board has a built-in RMS power detector that accurately determines the signal power and the noise power all along the demodulation process. Once the input signal and noise power is set for 0-dB input SNR, the noise power on the Type NS-1 Noise Source can be reduced in 1-dB steps to increase the SNR. The ASK and FSK signals are generated by the Type MOD-1 Signal Modulator board and the Type BER-1 BER Measurement board displays the Bit Error Ratio (BER) as a function of the Noise Power level from the NS-1 Noise Source (therefore sets the SNR).  The Type NCD-1 demodulates pseudorandom ASK and FSK data from the Type MOD-1