University of Edinburgh

Electrical Engineering

Data Converter Design in Simulink

Simulink Design Assignment

Design an audio band ADC with the following specifications over 20 Hz - 20 kHz:

[1] Maximum stable input amplitude (MSA) at least +/-0.85 for a full-scale input range of +/-1.0.

[2] Signal to quantisation noise ratio at MSA at least 105 dB.

[3] Total (audio band only) harmonic distortion at input level 1 dB below MSA less than -95 dB.

[4] NO audio band limit cycles or tones exceeding the quantisation noise power (i.e., no visible spurious

peaks rising above the noise floor)

You may choose ANY appropriate modulator architecture (order, quantisation levels, OSR). Remember

to clearly state and justify any design decisions or calculations you make.

A standard 24.576 MHz master clock is available (512×the common 48 kHz hi-fi audio Nyquist rate).

You may use any modulator sample rate derived by dividing the master clock by a power of 2, e.g.

24.576 MHz, 12.288 MHz, 6.144 MHz, 3.072 MHz, 1.536 MHz etc.

You should design your modulator using Simulink system level (choose from any of the modulator

schematics in labs 1-5 or define your own).

Your report should contain the following (in the order suggested):

1. Justify the choice of modulator structure, which may be drawn from those within the libraries made

available during the lab sessions OR your own custom structure. You may use the sigma-delta design

toolbox to synthesize the coefficients for higher order structures. Print and include the Simulink

schematic of your modulator. (20%)

2. Justify the modulator order, oversampling ratio, use (or not) of multi-bit feedback and dynamic

element matching scheme (including any element matching assumptions), use (or not) of dither.

Include a conclusions and summary table of all specs, modulator options considered and performances.

(20%)

3. Include all appropriate design calculations and simulations to confirm that the chosen modulator meets

the specification under the assumption of ideal components. (10%)

4. Perform a full set of Simulink simulations demonstrating your modulator’s tolerance of finite dc

integrator gain, coefficient mismatch, practical DAC element mismatch and integrator saturation

ISAT=1. (25%)

5. Demonstrate your modulator’s stability and absence of limit cycle tones under different input

conditions (frequency, amplitude, dc, step etc.) for ideal and non-ideal components. (15%)

6. Demonstrate the dynamic range scaling of the integrator outputs. (10%)

Your report should be maximum 20 pages in length (not including any Appendices).

Assignment issued Wednesday 15th January 2025.

Assignment hand-in date Monday 24th March 2025 before 2pm via Turnitin.