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Mixer - Complex baseband model of mixer and local oscillator with phase noise

Library

Mathematical

Description

The Mixer block generates a complex baseband model of the following:

• A mixer

• A local oscillator with phase noise whose spectrum is characterized by a 1/f slope

The Mixer block includes both the IF and RF signals as complex-baseband equivalent signals. Both the IF and RF center frequencies are represented as 0 hertz. The amplitude of the noise spectrum is specified by the noise power contained in a 1-hertz bandwidth offset from the carrier by a specified frequency.

Note   This block assumes a nominal impedance of 1 ohm.

The block applies the phase noise to the signal as follows:

1. Generates additive white Gaussian noise (AWGN) and filters it with a digital filter.

2. Adds the resulting phase noise to the angle component of the input signal.

You can view the block's implementation of phase noise by right-clicking the block and selecting Look under mask from the pop-up menu. The following figure shows the implementation.

You can view the construction of the Noise Source subsystem by double-clicking it.

Dialog Box

You can change parameters that are marked as tunable in the following descriptions while the model is running.

Conversion gain (dB)

Scalar specifying the conversion gain for the mixer. Use a negative value to specify loss. Tunable.

Phase noise level (dBc/Hz)

Scalar specifying the phase noise level in decibels relative to the carrier, per hertz. Tunable.

Frequency offset (Hz)

Scalar specifying the frequency offset. Tunable.

Initial seed

Nonnegative integer specifying the initial seed for the random number generator the block uses to generate noise.

References

[1] Kasdin, N.J., "Discrete Simulation of Colored Noise and Stochastic Processes and 1/(f^alpha); Power Law Noise Generation," The Proceedings of the IEEE, May, 1995, Vol. 83, No. 5.

See Also

Amplifier, Bandpass RF Filter, Bandstop RF Filter, Highpass RF Filter, Lowpass RF Filter

Microstrip Transmission Line

Output Port

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