Phase locked frequency synthesizer with single input wideband modulationsystem

Abstract From the Canadian patent

A single input wideband modulation system for a phase locked loop is achieved by interposing the inverse analogue of the closed phase locked loop transfer function between the modulation source and the VCO modulation input. A first branch of the interposed circuit directly passes high frequency signals from the modulation source to a summing device tied to an input of the VCO. A second branch of the interposed circuit boosts low frequency signals and blocks high frequency signals received from the modulation source and passes such signals to the summing device where signals from the first and second branches are summed to permit wideband modulation of the VCO. All the modulation processing …