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Delta Sigma Modulator

Model a discrete delta sigma modulator ADC

  • Library:
  • Mixed-Signal Blockset / ADC / Building Blocks

  • Delta-Sigma Modulator

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

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Analog input signal, specified as a scalar.

Data Types: double

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

Data Types: double

Output

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Digital output signal, returned as a scalar.

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

Parameters

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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

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 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

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

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]

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]

Resonator coefficients, specified as a vector with real elements.

Programmatic Use

Block parameter: g
Type: character vector
Values: real valued vector
Default: [0.014544]

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]

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 calculations in the delta sigma modulator ADC.

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

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

Bandwidth of the delta sigma modulator system,

Programmatic Use

Block parameter: BandWidth
Type: character vector
Values: nonnegative real scalar
Default: 1000
Switch Capacitors

Click to turn on the calculation of switched capacitance.

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 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 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:

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

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 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 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 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 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

Click to calculate the switched capacitance.

Introduced in R2021b