IMT Mixer
Model mixer using intermodulation table (IMT)
- Library:
RF Blockset / Circuit Envelope / Elements
Description
Use the IMT Mixer to perform frequency translation defined in an intermodulation table (see [1], [2], [3], and [4]) for a single tone carrier mixed with a local oscillator (LO) signal. The block includes nonlinear amplification, device and phase noise, and mixer spur visualization. For a single tone carrier Fcar nonlinearly modulated with an LO signal of frequency FLO, the mixer output intermodulation products occur at frequencies:
where:
Fcar – input RF signal carrier frequency
FLO – local oscillator frequency
M and N are nonnegative integers (0,1,…, order of nonlinearity)
For a downconverter, the desired output tone is , and for an upconverter it is . All other combinations of M and N represent the spurious intermodulation products.
Parameters
Carrier frequency (Hz) — Carrier frequency
1e9 (default) | scalar
Carrier frequency, specified as a scalar in hertz. When multiple carriers exist on the input connection, this carrier frequency is selected as the RF signal input. Distance between adjacent carriers must be greater than .
Data Types: double
Local oscillator frequency (Hz) — Local oscillator (LO) frequency
0.9e9 (default) | scalar
Local oscillator (LO) frequency, specified as a scalar in hertz.
Reference input power (dBm) — Reference input power
-10 (default) | scalar
Reference input power, specified as a scalar in dBm. The expression for the normalized input signal for the specified reference input power is:
Nominal output power (dbm) — Nominal LO power
-20 (default) | scalar
Nominal output power, specified as a scalar in dBm. The expression for the normalized output signal for the specified reference input power is:
Use data file — Specify data file to use
off (default) | on
Select this parameter to specify the data file you want to use to extract the spur table. Clear to specify your own spur values. The data file may contain any combination of IMT table and colored spot noise in s2d or p2d format. See [4].
Data file — Data file
samplespur1.s2d (default) |
Data file, specified as IMT data and colored spot noise.
Dependencies
To set this parameter, first select Use data file.
Input impedance (Ohm) — Input impedance of mixer
50
(default) | real scalar
Input impedance of mixer, specified as a real scalar.
Output impedance (Ohm) — Output impedance of mixer
50 (default) | real scalar
Output impedance of mixer, specified as a real scalar.
Ground and hide negative terminals — Ground RF negative circuit terminals
on (default) | off
Select this parameter to internally ground and hide the negative terminals. To expose the negative terminals, clear this parameter. If the terminals are exposed, the input signal is not referenced to the ground.
IMT table — IMT spur visualization
[99 99 99; 99 0 99; 99 99 99] (default) | square matrix
IMT spur visualization, specified as a square matrix.
Output signal power (dBm) — Signal power of desired output tone
0 (default) | scalar
Signal power of the desired output tone when plotting intermodulation products, specified as a scalar.
Mixer type — Mixer type
Upconverter (default) | Downconverter
Mixer type, specified as Upconverter or
Downconverter.
Plot — Visualize IMT table values using specified signal power and mixer type
button
Visualize IMT table values using specified signal power and mixer type.
Simulate noise — Simulate device or phase noise
on (default) | off
Select this parameter to simulate noise as specified in block parameters or in file.
If the noise is specified in an .s2p file, then it is
used for simulation.
Noise type — Noise type
Noise figure (default) | Spot noise data
Noise type, specified as Noise figure or
Spot noise data.
Dependencies
To set this parameter, first select Simulate noise.
Noise distribution — Noise distribution
White (default) | Piece-wise linear | Colored
Noise distribution, specified as:
White– Spectral density is a single nonnegative value. The power value of the noise depends on the bandwidth of the carrier, and the bandwidth depends on the time step. This is an uncorrelated noise source.Piece-wise linear– Spectral density is a vector of values [pi]. For each carrier, the noise source behaves like a white uncorrelated noise. The power of the noise source is carrier dependent.Colored– Depends on both carrier and bandwidth. This is a correlated noise source.
Dependencies
To set this parameter, first select Simulate noise.
Noise figure (dB) — Noise figure
0 (default) | scalar
Noise figure, specified as a scalar in decibels.
Dependencies
To set this parameter, first select Simulate noise.
Frequencies (Hz) — Frequency data
0 (default) | scalar | vector
Frequency data, specified as a scalar for white noise or vector for piece-wise linear or colored noise in hertz.
Dependencies
To set this parameter, first select Select noise
then select Piece-wise linear or
Colored in Noise
distribution.
Minimum noise figure (dB) — Minimum noise figure
0 (default) | scalar | vector
Minimum noise figure, specified as a scalar or vector in decibels.
Dependencies
To set this parameter, first select Spot noise
data in Noise type.
Dependencies
To set this parameter, first select Select noise
then select Spot noise data in
Noise Type.
Optimal reflection coefficient — Optimal reflection coefficient
0 (default) | scalar | vector
Optimal reflection coefficient, specified as a scalar or a vector.
Dependencies
To set this parameter, first select Select noise
then select Spot noise data in
Noise Type.
Equivalent normalized noise resistance — Equivalent normalized noise resistance
0 (default) | scalar | vector
Equivalent normalized noise resistance, specified as a scalar or vector.
Dependencies
To set this parameter, first select Select noise
then select Spot noise data in
Noise Type.
Add LO phase noise — Add phase noise
off (default) | on
Select this parameter to add phase noise to your system with a continuous wave source.
Dependencies
To set this parameter, select Simulate noise.
Phase noise frequency offset (Hz) — Phase noise frequency offset
1 (default) | scalar | vector
Phase noise frequency offset with respect to LO signal, specified as a scalar or vector with each element unit in hertz.
The frequency offset values must be bounded by the envelope bandwidth of the simulation. For more information see Configuration.
Dependencies
To enable this parameter, first select Simulate noise then select Add phase noise.
Phase noise level (dBc/Hz) — Phase noise level
-Inf (default) | scalar | vector | matrix
Phase noise level, specified as a scalar or vector or matrix with elements in decibel per hertz.
If you specify a matrix, each column should correspond to a non-DC carrier frequency of the CW source. The frequency offset values must be bounded by the envelope bandwidth of the simulation. For more information see Configuration.
Dependencies
To enable this parameter, first select Simulate noise then select Add phase noise.
Automatically estimate impulse response duration — Automatically estimate impulse response duration
on (default) | off
Select this parameter to automatically calculate impulse response for frequency-dependent noises. Clear this parameter to manually specify the impulse response duration using Impulse response duration.
Dependencies
To enable this parameter, first select Simulate noise then select Add phase noise.
Impulse response duration — Impulse response duration
1e-10s (default) | scalar
Impulse response duration used to simulate frequency-dependent noise,
specified as a scalar in seconds. The time should be an integer multiple of
the step size in the configuration block,
Tduration =
NTstep.
Dependencies
To set this parameter, first clear Automatically estimate impulse response duration.
References
[1] https://www.mathworks.com/help/rf/examples/visualizing-mixer-spurs.html
[2] https://www.microwavejournal.com/articles/3430-the-use-of-intermodulation-tables-for-mixer-simulations
[3] https://www.electronics-notes.com/articles/radio/rf-mixer/rf-mixing-basics.php
[4] https://www.mathworks.com/help/rf/examples/rf-data-objects.html