A True Logarithmic IF Amplifier for Radar Applications

摘要

The availability of VX(M)9410 True Logarithmic IF amplifier stages as integrated circuits has enabled IF logarithmic amplifiers to be constructed by cascading stages with more than 60 dB's of dynamic range. True logarithmic amplifiers have an advantage over normal successive detection logarithmic amplifiers as the compression is achieved at Intermediate Frequency and not at Video Frequency thus preserving the phase information. Logarithmic amplifiers are required in many applications where phase and amplitude is of importance, examples are monopulse, MTI and ECM Radars. For multichannel receivers the requirement is to minimise phase shift through the logarithmic amplifier with change of signal level. This report describes measurements carried out on a number of true logarithmic amplifiers, and particular attention has been given to measurements of phase and amplitude tracking of amplifiers. The Constant False Alarm Rate (CFAR) properties have also been investigated. (Author)