There is a genera requirement (not only for low-cost phasing networks) to be able accurately to compare capacitors (and resistors) taken from a batch of wider tolerance components to select components that match to within, say, ±1%. It is possible to buy low-tolerance capacitors and resistors at a cost premium. Andre Jamet, F9HX, who has recently constructed a 144MHzSSBtransceiverusing Hilbert (two path) phasing circuits rather than a four-path poly phase network, notes that both two- and four-path methods call for precise matching of resistors and capacitors to achieve the theoretically possible sideband discrimination.
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