Discussion in 'Homework Help' started by praveen450, Aug 1, 2011.

  1. praveen450

    Thread Starter New Member

    Aug 1, 2011
    [​IMG][​IMG]x(t) is multiplied by exp(-j2*pi*fo*n) followed by LPF and decimator (16)

    The incoming signal is assumed to be obtained from a
    continuous-time signal xc(t) using a sample rate of Fx = 48 ksps. The value of f0 is selected as 12.5/48, so that the
    system analyzes a desired “signal band” centered at 12:5 kHz. For the purposes of this quiz, assume that the incoming
    “signal band” is 11:5 kHz < F < 13:5 kHz.
    Because the bandwidth of the signal at the output of the lowpass filter is greatly reduced, the sample rate is to
    be reduced by the decimator as shown in the figure. For this quiz, you are to determine the required lowpass filter
    specification such that:
    Signals within the “signal band” are passed with gain 0 dB 0.2 dB.
    Signals which would alias into the “signal band” when the sample rate is reduced are attenuated by at least
    70 dB.

    Can anyone suggest an approach to this problem?.:(
  2. guitarguy12387

    Active Member

    Apr 10, 2008
    Are you supposed to use an FIR or an IIR filter? I suppose FDAtool is out of the question for a quiz... haha!

    Also, you will need to know your transition band of the filter. No such thing as a brickwall filter
  3. guitarguy12387

    Active Member

    Apr 10, 2008
    Or do we assume that no signal exists between 13.5k and 24k?