Mixer
RF and IQ modulator and demodulator models with interference and noise.
blockType: Mixer
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Path in the library: |
Description
Block Mixer It consists of four integrated baseband mixers, as well as interference and noise. The unit models four types of mixers: modulator, demodulator, IQ modulator and IQ demodulator. Signal distortions are IQ amplification and phase misalignment, where necessary, and noise includes system and LO phase noise.
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An idealized block model Mixer assumes that the input and output ports are consistent.
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An idealized block model Mixer it is single-band with an assumed value of the carrier frequency. Therefore, the block Mixer It can generate only one sideband at the output.
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The mask icons of the mixer blocks are dynamic and indicate the current set of applied noise parameters. For more information, see Mixer block icons.
Ports
Input
#
Input
—
time-dependent input signal
real scalar | real column | complex scalar | complex column
Details
A time-dependent input signal specified as a real scalar or column, complex scalar or column. The column represents consecutive time points.
| Data types |
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| Complex numbers support |
Yes |
Output
#
Output
—
time-dependent output signal
complex scalar | complex column
Details
A time-dependent output signal returned as a complex scalar or column. The size of the output signal is equal to the size of the input signal.
| Data types |
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| Complex numbers support |
Yes |
Parameters
Main
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Type of mixer —
mixer type
mod | demod | iqmod | iqdemod
Details
The type of mixer. Set as:
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`mod' – modulator
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`demod' – demodulator
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'iqmod' – IQ modulator
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'iqdemod' – IQ demodulator
| Values |
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| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
No |
#
Conversion gain for mixer (dB) —
conversion factor for mixer
Real number
Details
The conversion gain for the mixer model, set as a real number.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
Sidebands of mixer —
mixer side strips
lower | upper
Details
Side strips of the mixer. Are set as:
-
lower -
upper
Dependencies
To use this parameter, set the Mixer type parameter to mod.
| Values |
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| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
No |
#
Rf carrier frequency (Hz) —
frequency of the carrier radio frequency
Real number
Details
The frequency of the radio carrier frequency for the mixer model, set as a real number.
Dependencies
To use this parameter, set the Mixer type parameter to mod, demod or `iqdemod'.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
Local oscillator frequency (Hz) —
frequency of the local oscillator
Real number
Details
The frequency of the local oscillator for the mixer model, specified as a real number.
Dependencies
To use this parameter, set the Mixer type parameter to mod, demod or `iqdemod'.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
Main
#
LO phase offset (deg) —
LO phase offset
Real number
Details
The phase offset LO, specified as a real number.
Dependencies
To use this parameter, set the Mixer type parameter to mod or demod.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
IQ gain imbalance (dB) —
IQ gain imbalance
Real number
Details
The imbalance of the IQ gain factor, given as a non-negative real number.
Dependencies
To use this parameter, set the Mixer type parameter to iqmod or `iqdemod'.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
IQ phase imbalance (deg) —
imbalance of IQ phases
Real number
Details
The imbalance of IQ phases, given as a real number.
Dependencies
To use this parameter, set the Mixer type parameter to iqmod or `iqdemod'.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
Third-order nonlinearity type —
type of third-order nonlinearity
IIP3 | OIP3 | IP1dB | OP1dB | IPsat | OPsat
Details
A type of third-order nonlinearity in a cubic polynomial model. Set as:
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IIP3 -
OIP3 -
IP1dB -
OP1dB -
IPsat -
OPsat
| Values |
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| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
No |
#
Input third-order intercept point —
the third-order intercept entry point
Real number
Details
The intercept point of the third order, given as a real positive number.
Dependencies
To use this parameter, set the Third-order nonlinearity type parameter to IIP3.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
Output third-order intercept point —
the output intercept point of the third order
Real number
Details
The output intercept point of the third order, specified as a real positive number.
Dependencies
To use this parameter, set the Third-order nonlinearity type parameter to OIP3.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
Input 1 dB compression point —
The input compression point is 1 dB
Real number
Details
The input compression point is 1 dB, specified as a real positive number.
Dependencies
To use this parameter, set the Third-order nonlinearity type parameter to IP1dB.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
Output 1 dB compression point —
The output compression point is 1 dB
Real number
Details
The output compression point is 1 dB, specified as a real positive number.
Dependencies
To use this parameter, set the Third-order nonlinearity type parameter to OP1dB.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
Input saturation point —
input saturation point
Real number
Details
The saturation point of the input, set as a real positive number.
Dependencies
To use this parameter, set the Third-order nonlinearity type parameter to IPsat.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
Output saturation point —
output saturation point
Real number
Details
The saturation point of the output, set as a positive real number.
Dependencies
To use this parameter, set the Third-order nonlinearity type parameter to OPsat.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
Main
#
Options to mixer noise to system —
inclusion of noise from the mixer in the system
Logical
Details
Select this option to add mixer noise to the input signal.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
No |
#
Type of noise —
type of noise
noise-temperature | NF | noise-factor
Details
The type of noise. Set as:
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noise-temperature– noise temperature -
`NF' is the noise factor.
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'noise-factor` – noise factor
Dependencies
To use this option, check the box for Options to mixer noise to system.
| Values |
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| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
No |
# Noise temperature (K) — mixer noise temperature
Details
The noise temperature for mixer noise simulation, set as a non-negative real number.
Dependencies
To use this parameter, check the Options to mixer noise to system checkbox and set the Type of noise parameter to noise-temperature.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
Noise figure (dB) —
mixer noise ratio
Real number
Details
The noise coefficient for modeling mixer noise is set as a non-negative real number.
Dependencies
To use this parameter, check the Options to mixer noise to system checkbox and set the Type of noise parameter to NF.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
Noise factor to model mixer noise —
mixer noise ratio
Real number
Details
The noise coefficient for modeling mixer noise is given as a positive integer scalar, .
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
Source of initial seed —
source of the initial value
auto | user
Details
The source of the initial value used to prepare a random number Gaussian noise generator. Set as:
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auto– The source for each mixer is generated using a random number generator. The instance reset method has no effect. -
user' – if the Source of initial seed parameter is set to `auto, the value specified in the Seed for random number generator parameter is used to initialize the random number generator, and the reset method resets the random number generator using the value of the Seed for random number generator property.
Dependencies
To use this option, check the box for Options to mixer noise to system or Add LO phase noise to LO signal.
| Values |
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| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
No |
#
Seed for random number generator —
the source for the random number generator
Real number
Details
The initial value for the random number generator, set as a non-negative integer, . Use this value to initialize the random number generator.
Dependencies
To use this parameter, check the Options to mixer noise to system or Add LO phase noise to LO signal option and set the Source of initial seed parameter to user.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
Add LO phase noise to LO signal —
turning on the LO phase noise to the LO signal
Logical
Details
Select this option to add LO phase noise to the LO signal depending on the frequency.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
No |
#
Phase noise level (dBc/Hz) —
phase noise level relative to the carrier
Scalar / array of real numbers
Details
The phase noise level relative to the carrier, specified as a negative real scalar or vector.
| The number of values listed in the Phase noise level relative to carrier parameter must be equal to the number of values in the Phase frequency offset parameter. |
Dependencies
To use this option, check the box for the Add LO phase noise to LO signal option.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
Frequency offset (Hz) —
phase frequency shift
Scalar / array of real numbers
Details
Frequency offset in the form of a positive real scalar or a vector of positive increasing real values.
| The number of values listed in the Phase frequency offset parameter must be equal to the number of values in the Phase noise level relative to carrier parameter. |
Dependencies
To use this option, check the box for the Add LO phase noise to LO signal option.
| Default value |
|
| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
Options to automatically determine number of frequency bins —
enabling automatic detection of the number of frequency bins
Logical
Details
Select this option to automatically determine the number of frequency bins used in the two-way phase noise spectrum.
Dependencies
To use this option, check the Options to mixer noise to system and Add LO phase noise to LO signal boxes.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
No |
#
Number of sample in time-domain signal —
the number of samples in the time domain signal
Real number
Details
The number of samples in the time domain signal for the sampling period blocks or the number of frequency lines (bins) in the two-way frequency spectrum of the signal to achieve the required frequency resolution for a given frequency offset, specified as a valid non-negative integer, . The frequency resolution increases as the value of the number of samples of the signal increases.
| The value of this parameter must be a power of two. |
Dependencies
To use this option, check the Options to mixer noise to system and Add LO phase noise to LO signal boxes.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
Source of initial seed —
the description is missing
auto | user
Details
the description is missing
| Values |
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| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
No |
#
Seed for random number generator —
the description is missing
Real number
Details
The description is missing.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
Algorithms
Architectures and design equations of the Mixer block
Architectural models for the block are presented here. Mixer. The mixer and phase noise data for all cases are shown here.
Modulators and demodulators
The architectures of the modulator and demodulator include system noise, phase noise, and nonlinear carrier translation polynomials. A random number generator is used as an input to generate phase noise.
The output signal of an ideal modulator and demodulator circuit with non-linearities, , is given by this equation:
where
IQ modulator
The primary IQ modulator consists of two mixers, and . Mixers convert baseband signals to RF signals and are commonly used in direct conversion architectures. Mixers and They are responsible for introducing gain, gain imbalance, phase imbalance, and non-linearity into the IQ demodulator.
IQ modulator output signal, , is defined as:
where
Linear gain factors of modulators and are given in the equation:
where
IQ demodulator
The architecture of the IQ demodulator is shown below. Common - mode, , and the quadrature component, , the modulated signal are the output and accordingly. Mixers, and , are responsible for introducing gain, gain imbalance, phase imbalance, and non-linearity into the IQ demodulator.
IQ Demodulator output, , has the form
where
Linear gain factors of modulators and are given in this equation.
where
Side stripes of the Mixer block
Upper and lower side ranges
The expression for shows the formation of upper and lower side stripes, and , and the effect of the difference in the values of the input carrier and the LO signal on the sinusoidal function. Application of the trigonometric identity:
to express the product of mixers, , gives
where is the term associated with the higher output frequency, , is the upper side band, and – lower side stripe. Set the Type of mixer parameter to mod.
For demodulators, only the lower sideband can be used as an output.
Selecting a mixer by type
When selecting the mixer type, this table shows the available sideband options according to the block parameters LO phase offset, IQ gain imbalance and IQ phase imbalance.
| Mixer type | Distortions | Noise |
|---|---|---|
The modulator |
LO phase shift and non-linearity. |
LO phase shift, mixer and system noise. |
Demodulator |
||
IQ modulator/demodulator |
Gain imbalance, phase imbalance, and non-linearity. |
Mixer Block icons
This table shows how the block icons will change depending on the values of the Type of mixer, Options to mixer noise to system and Add LO phase noise to LO signal parameters.
| Type of mixer | Options to mixer noise to system | Add LO phase noise to LO signal: off. | Add LO phase noise to LO signal: on. |
|---|---|---|---|
The modulator
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Demodulator
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IQ Modulator
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IQ Demodulator
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Literature
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Razavi, Behzad. "Basic Concepts in RF Microelectronics", 2nd edition, Prentice Hall, 2012.
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Kundert, Ken."Accurate and Rapid Measurement of IP2 and IP3," The Designer Guide Community, May 22, 2002.
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Kasdin, N.J. "Discrete Simulation of Colored Noise and Stochastic Processes and 1/f α Power Law Noise Generation." Proceedings of the IEEE 83, no. 5 (May 1995): 802–27. https://doi.org/10.1109/5.381848.