Thanks for the reply, what does sound level refer to? Is it the amplitude.
Also,the sampling rate is taken as twice of the highest frequency (since signal contains complex signals),the will the reconstructed signal have this frequency?
my doubt is , how does a digital data is converted into frequency varying analog signal.
that is from an adc we get amplitude of the analog signal,but what causes the variations in frequency?
i need to design the circuit to decode a morse code which will be transmitted in this range,the IC TDA 7000 does not satisfy the frequency range criteria.It works in the range of 70 to 120 MHz range. Can i use a mixer to lower the incoming frequency to this range and than use it?