Simple logarithmic pulse height analysers

A type of multichannel analyser is described in which the pulse height is encoded by applying it to a ringing circuit and counting the number of cycles before the oscillation decays to a fixed level. With a 10% channel width the dynamic range of the 64 channel instrument described is 400:1. Possible types of read-out are discussed and various solutions suggested that are compatible with the simplicity, reliability and stability of the remainder of the analyser.