Design and realisation of practical wideband quadrature networks with linear phase-shift characteristics

Two approaches to the design of wideband quadrature networks with linear phase-shift characteristics are considered. The first involves equalising the delay characteristics of networks derived using the well known elliptic-function method; the second uses a more direct design method suggested by Herrmann in 1969. An assessment is made of the suitability of each approach for practical applications at video frequencies. As a result, an extension of Herrman´s method is proposed which is shown to be less restrictive than the elliptic-function method and to produce networks whose performance is more predictable. Tables of design data are presented and a practical example is included to demonstrate their use.