RxCalc

RxCalc is a calculator for the analysis of multi-stage receiver. The software can calculate cascaded and system parameters: gain, noise, sensitivity, input and output P1dB and IP3, noise floor, spur-free dynamic range, MDS, SNR, and others.

Sources code: https://github.com/arhiv6/rxcalc

Binary package: http://sourceforge.net/projects/rxcalc/