Delta Sigma Modulator

Model a discrete delta sigma modulator ADC

• Library:

• Mixed-Signal Blockset / ADC / Building Blocks

• 

Description

Use the Delta Sigma Modulator block to model a discrete delta sigma modulator based ADC using a set of different architectures such as cascade of feedback or feed-forward resonators or integrators.​ You can model an ADC of orders two to six. You can model circuit based noise and also get accurate switched capacitor values used in actual circuit design and layout.

Ports

Input

In — Analog input signal

scalar

Analog input signal, specified as a scalar.

Data Types: double

Reset — Reset Delta Sigma Modulator

scalar

Reset signal for Delta Sigma Modulator block, specified as a scalar.

Data Types: double

Output

Out — Digital output signal

scalar

Digital output signal, returned as a scalar.

Data Types: fixed point | single | double | int8 | int16 | int32 | uint8 | uint16 | uint32 | Boolean

Parameters

Delta Sigma Modulator architecture — Architecture of delta sigma modulator

CIFB (default) | CRFB | CIFF | CRFF

Architecture of the delta sigma modulator, specified as:

• CIFB — cascade of feedback integrators.

• CRFB — cascade of feedback resonators.

• CIFF — cascade of feed-forward integrators.

• CRFF — cascade of feed-forward resonators.

Programmatic Use

Block parameter: dsmArchitecture

Type: character vector

Values: CIFB | CRFB | CIFF | CRFF

Default: CIFB

Delta Sigma Modulator order — Order of delta sigma modulator

2nd order (default) | 3rd order | 4th order | 5th order | 6th order

Order of delta sigma modulator. You can choose between orders two to six.

Programmatic Use

Block parameter: dsmOrder

Type: character vector

Values: 2nd order | 3rd order | 4th order | 5th order | 6th order

Default: 2nd order

Input Parameters

Sampling frequency (Hz) — Sampling frequency of delta sigma modulator

50000 (default) | positive real scalar

Sampling frequency of the delta sigma modulator, specified as a positive real scalar in Hz.

Programmatic Use

Block parameter: SamplingFrequency

Type: character vector

Values: positive real scalar

Default: 50000

Quantizer levels — Number of quantizer levels in delta sigma modulator

2 (default) | positive real scalar

Number of quantizer levels in delta sigma modulator, specified as a positive real scalar.

Programmatic Use

Block parameter: NumberLevels

Type: character vector

Values: positive real scalar

Default: 2

Quantizer ouput — Range of quantizer output

[-1;1] (default) | real valued vector

Range of the quantizer output in the delta sigma modulator architecture, specified as a vector with real elements.

Programmatic Use

Block parameter: QuantizerOutput

Type: character vector

Values: real valued vector

Default: [-1;1]

Coefficient 'a' — Feedback/feed-forward coefficients from/to the quantizer

real valued vector

Feedback coefficients from the quantizer or feed-forward coefficients to the quantizer, specified as a vector with real elements.

Programmatic Use

Block parameter: a

Type: character vector

Values: real valued vector

Default: [0.26017;0.2207]

Coefficient 'g' — Resonator coefficients

real valued vector

Resonator coefficients, specified as a vector with real elements.

Programmatic Use

Block parameter: g

Type: character vector

Values: real valued vector

Default: [0.014544]

Coefficient 'b' — Feed-in coefficients from the modulator input to each integrator

real valued vector

Feed-in coefficients from the modulator input to each integrator, specified as a vector with real elements.

Programmatic Use

Block parameter: b

Type: character vector

Values: real valued vector

Default: [0.26017;0;0]

Coefficient 'c' — Integrator inter-stage coefficients

real valued vector

Integrator inter-stage coefficients, specified as a vector with real elements.

Programmatic Use

Block parameter: c

Type: character vector

Values: real valued vector

Default: [0.36129;6.8191]

Noise

Enable Noise Impairment — Enable noise calculations in delta sigma modulator ADC

on (default) | off

Enable noise calculations in the delta sigma modulator ADC.

Signal to noise ratio (dB) — Ratio of signal power to noise power

75 (default) | nonnegative real scalar

Ratio of signal power to noise power, specified as a nonnegative real scalar in dB.

Programmatic Use

Block parameter: SNR

Type: character vector

Values: nonnegative real scalar

Default: 75

Input Signal Power (W) — Power of input signal

0.125 (default) | real scalar

Power of the signal at the input of the delta sigma modulator, specified as a real scalar in watts.

Programmatic Use

Block parameter: InputPower

Type: character vector

Values: real scalar

Default: 0.125

System Bandwidth (Hz) — Bandwidth of delta sigma modulator system

1000 (default) | nonnegative real scalar

Bandwidth of the delta sigma modulator system,

Programmatic Use

Block parameter: BandWidth

Type: character vector

Values: nonnegative real scalar

Default: 1000

Switch Capacitors

Enable switched capacitance calculation — Enable calculation of switched capacitance

off (default) | on

Click to turn on the calculation of switched capacitance.

Over Sampling Ratio — Ratio of delta sigma modulator sampling rate to Nyquist rate

25 (default) | nonnegative real scalar

Ratio of the delta sigma modulator sampling rate to the Nyquist rate, defined as a nonnegative real scalar. A high oversampling ratio results in a relaxed anti-aliasing filter and reduced in-band quantization noise.

Programmatic Use

Block parameter: OSR

Type: character vector

Values: nonnegative real scalar

Default: 25

Target signal to noise ratio (dB) — Target SNR of delta sigma modulator system

75 (default) | nonnegative real scalar

Target SNR of the delta sigma modulator system, defined as a nonnegative real scalar in dB.

Programmatic Use

Block parameter: capacitorSNR

Type: character vector

Values: nonnegative real scalar

Default: 75

Supply Voltage (V) — Supply voltage value of CMOS technology

1 (default) | nonnegative real scalar

Supply voltage value of the CMOS technology used to design the delta sigma modulator, specified as a nonnegative real scalar. The Supply Voltage (V) is defined in the PDK.

Programmatic Use

Block parameter: SupplyRail

Type: character vector

Values: nonnegative real scalar

Default:

Input Signal Swing (V) — Estimated input signal swing in CMOS technology

0.2 (default) | nonnegative real scalar

Estimated input signal swing in the CMOS technology used to design the delta sigma modulator, specified as a nonnegative real scalar in voltage. The Input Signal Swing (V) is defined in the PDK.

Programmatic Use

Block parameter: VInput

Type: character vector

Values: nonnegative real scalar

Default: 0.2

Reference Voltage (V) — Typical reference voltage value for CMOS technology

0.3 (default) | nonnegative real scalar

Typical reference voltage value for the CMOS technology used to design the delta sigma modulator, specified as a nonnegative real scalar in voltage. The Reference Voltage (V) is defined in the PDK.

Programmatic Use

Block parameter: VReference

Type: character vector

Values: nonnegative real scalar

Default: 0.3

Capacitor Density (ff/um) — Capacitor density of CMOS technology

1.5 (default) | nonnegative real scalar

Capacitor density of the CMOS technology used to design the delta sigma modulator, specified as a nonnegative real scalar in ff/µm. The Capacitor Density (ff/um) is defined in the PDK.

Programmatic Use

Block parameter: CapacitorDensity

Type: character vector

Values: nonnegative real scalar

Default: 1.5

Fringe Capacitance (ff/um) — Fringe capacitance of CMOS technology

0.2 (default) | nonnegative real scalar

Fringe capacitance of the CMOS technology used to design the delta sigma modulator, specified as a nonnegative real scalar in ff/µm. The Fringe Capacitance (ff/um) is defined in the PDK.

Programmatic Use

Block parameter: FringeCapacitor

Type: character vector

Values: nonnegative real scalar

Default: 0.2

Capacitor Temperature Coefficient (ppm/deg-C) — Capacitor temperature coefficient in CMOS technology

2.2 (default) | nonnegative real scalar

Capacitor temperature coefficient in the CMOS technology used to design the delta sigma modulator, specified as a nonnegative real scalar in ppm/℃. The Capacitor Temperature Coefficient (ppm/deg-C) is defined in the PDK.

Programmatic Use

Block parameter: CapacitorCoefficient

Type: character vector

Values: nonnegative real scalar

Default: 2.2

Minimum Grid Step (um) — Minimum grid step allowed for designing capacitor layout

0.005 (default) | nonnegative real scalar

Minimum grid step allowed for designing the capacitor layout, specified as a nonnegative real scalar in µm

Programmatic Use

Block parameter: GridStep

Type: character vector

Values: nonnegative real scalar

Default: 0.005

Calculate — Calculate switched capacitance

button

Click to calculate the switched capacitance.