Project submission

1. Give a clear description of the following in your report.
   • Prototype lowpass filter design; computation of zeros to get the boost at $f_s/2$ and attenuation at $f_s$.
   • Detailed design of the filter at the desired frequency with all the resistor/$g_m$ and capacitor values.
   • Scaling the filter to have equal maxima in the ac response at all opamp/$g_m$outputs. Scaling the filter to use a total capacitance of 2.xxpF.
   • A complete schematic with all the component values. Use a sensible hierarchy so that the design is understandable.
2. Before the due date(6 May 2003, 5pm) e-mail me your cadence library path that contains the project, and the name of the topmost cell in your hierarchy.
3. Submit the following simulation results.
   • Frequency response: magnitude response at the filter's output showing the gain boost at $f_s/2$ and the attenuation at $f_s$; group delay response; plot with overlaid magnitude response at all the opamp/$g_m$outputs.
   • Transient: Show the response of the filter for a single 1V pulse whose duration is $1/f_s = 1$ns.

     You will be given the waveforms of the bit streams at A and B. Simulate the filter with its input being the sum of the channel output and the clock feedthrough(100mV sinusoid at $1\,\,\mbox{GHz}$). Show the outputs of the transmitter and the channel(waveforms will be given to you) and the output of the filter. Briefly describe what your filter has done to the signal.

   • Noise: Show the noise spectral density at the output. Compute the integrated noise upto $f_s=1\,\mbox{GHz}$. Calculate the output signal to noise ratio, assuming that a 1V sinusoid at low frequencies is applied to the filter.
   • Power dissipation: Plot the frequency response magnitude(with an input magnitude of 1V) of the output currents of the each of the opamp/$g_m$. Tabulate the maximum of each of the current magnitudes over frequency. These will be the largest currents drawn from each opamp/$g_m$.

     If you are using opamps, take the largest of these and multiply by 8. This will be the current drawn per opamp. Multiply by the number of opamps to arrive at the total current dissipation. This means that you are using identical opamps which are capable of driving the largest current demanded in this circuit. This is a common situation in filter design.

     If you are using $g_m$s, multiply the largest current drawn from each $g_m$, by 8 and sum the result to obtain the total current dissipation. Note that you cannot in general use identical $g_m$s as the transfer function depends on the value of the $g_m$s.

     Compute the power dissipation assuming that the supply voltage is 2.5V.