# Amplifiers and Mixers

## Introduction

The *Filters* - <*filter type*> and *System* - <*device type* palettes contain two fundamentally different types of behavioral system models.

*Filters*, *System - Amps & Mixers*, and *System - Mod/Demod* can be classified as *tops-down system models* that support a tops-down system design flow where model behaviors are characterized by a small number of independent parameters such as frequency, power and load. They are often referred to as *parameter-based behavioral models*.

*System - Data Models* can be classified as *bottoms-up system models* that support a bottoms-up verification flow where model behaviors are extracted from a simulation (or measurement) of a transistor-level circuit. They are often referred to as *data-based behavioral models*.

The *parameter-based behavioral models* typically provide superior speed relative to the data-based behavioral models with both of these being vastly superior to a brute-force transistor-level simulation.

The *data-based behavioral models* ypically provide superior accuracy relative to the *parameter-based behavioral models* as they capture actual behaviors of implemented circuit components and not just design specifications.

The differences between *parameter*- and *data-based behavioral models* justify a palette emphasis on flow (all data-based behavioral models grouped together) rather than functionality (all amplifiers, mixers, modulators, and demodulators grouped together) and resulted in the addition of a *System - Data Models* palette.

The use model for parameter-based behavioral models is to simply set a series of parameters prior to using the model. The use model for data-based behavioral models is slightly more involved. For a discussion, see System Data Models.

## Curve-Fitting Algorithm

The curve-fitting algorithm to determine the nonlinear behavior of the system mixer models is based on fitting a polynomial to the specified data where the saturation power (Psat) is calculated when the derivative of this polynomial is zero.

Pn(x) = a1*x1+a2*x2^2+a3*x^3+...

It is important to note that the coefficients a4,a6,a8,...are always zero. In only one case a2 is non-zero and that's when SOI and TOI are specified.

Parameters |
Order |
---|---|

TOI |
3 |

TOI & AM2PM |
3 |

SOI & TOI |
3 a2 ≠ 0 |

PndB |
3 |

PndB & AM2PM |
3 |

Psat |
5 |

TOI & PndB |
5 |

PndB & Psat |
7 |

TOI & Psat |
7 |

PndB & TOI & Psat |
9 |

## Components

- AGC Amp (Voltage-Controlled Amplifier for AGC loops)
- AGC PwrControl (Power Control Block for AGC loops)
- Amplifier2 (RF System Amplifier)
- Amplifier (Obsolete RF System Amplifier)
- AmplifierVC (Ideal Voltage-Controlled Amplifier)
- AmpSingleCarrier (Single Carrier Amplifier)
- FreqMult (Ideal Frequency Multiplier)
- LogACDemod (Demodulating AC Logarithmic Amplifier)
- LogDC (DC Logarithmic Amplifier)
- LogSuccDetect (Successive Detection Logarithmic Amplifier
- LogTrue (True Logarithmic Amplifier)
- Mixer2 (RF System Mixer)
- Mixer (First RF System Mixer, Polynomial Model for Nonlinearity)
- MixerWithLO (Mixer with Internal Local Oscillator)
- OpAmp (Operational Amplifier)
- OpAmpIdeal (Ideal Operational Amplifier)
- VMult (Voltage Multiplier)