Introduction to ADMS RF (Digital AGC Loop)

"The objective of this technical paper is to provide an introduction to ADVance MS RF (abbreviated to ADMS RF in the rest of this text), using an example wherein the tool brings real benefits in terms of performance and usability.

Many digital communication systems include tightly integrated radio frequency (RF), analog/mixed-signal and DSP functions, which causes difficulties with classical transient simulation, because of the RF carriers.

ADMS RF specifically targets specifically these types of challenging simulations. It is basically an advanced simulation technique, leveraging the power of ADVance MS and the efficiency of the modulated steady-state algorithm in Eldo RF. ADVance MS and Eldo RF are respectively the analog/mixed-signal and RF simulators from Mentor Graphics.

This technical paper shows how ADMS RF can be used to efficiently simulate an automatic gain control (AGC) loop. The system is driven with a digitally modulated signal (GMSK). The different blocks in this loop are described in SPICE (transistor-level), Verilog-A (behavioral), and VHDL. The gain control is performed digitally.