Intermodulation noise reduction circuit - introduces phase shifters at regular intervals along repeater chain to produce phase shift constant over input bandwidth

摘要

The intermodulation noise reduction circuit, for a chain of repeater amplifiers in analog telephone, reduces final noise amplitude caused by nonlinearity of individual amplifiers. By placing phase shifters between adjacent amplifiers. By placing phase shifters between adjacent amplifiers to a phase shift is introduced along the chain that is constant over the input signal's bandwidth. The phase shifters can be inverting transformers. They may be placed along the amplifier chain with one every k repeaters. The vale of k may alternate along the chain.