8 Erratum and Addendum

After publication of this note I was contacted by Mike Gingell, KN4BS and learned that he is the inventor of this circuit along with others of this class known as ``sequence asymmetric polyphase networks.'' As expected, he was aware of most the results here with the possible exception of the application of Saraga's methods to form a Chebychev network. However, he told me that Saraga was one of his PhD examiners, so I don't think Saraga's methods were completely unknown to him.

Here are some references that he sent me that give more history.

1.

M.J.Gingell: ``A Symmetrical Polyphase Network'' British Patents 1,174,709 and 1,174,710 filed 7th June 1968, published 17 Dec 1969, US Patents 3,559,042 and 3,618,133 published Jan 26 1971

2.

M.J.Gingell: ``Single Sideband Modulation using Sequence Asymmetric Polyphase Networks'' Electrical Communication Magazine, Vol 48 No 1 and 2 combined 1973, p 21-25

3.

Pat Hawker, G3VA: ``Polyphase System for SSB Generation'' in ``Technical Topics'' Radio Communication Oct 73, p698-9

4.

Pat Hawker, G3VA: ``More on Polyphase SSB'' in ``Technical Topics'' Radio Communication Dec 73, p852-853

5.

M.J.Gingell: ``The Synthesis and Application of Polyphase Networks with Sequence Asymmetric Properties'' PhD Thesis University of London, 1975

6.

M.J.Gingell: ``Sequence Asymetric Polyphase Networks: Application to F D M'' IEE Colloquium on Applications of Active, Digital and Passive Filters, London, January 14 1975.

7.

Pat Hawker, G3VA: ``G3PLX polyphase SSB generator'' in ``Technical Topics'' Radio Communication May 1975, p379-381

8.

A. Gschwindt, HA5WH: ``Some Reflections on the four-way phasing method'' Radio Communication Jan 76, p28-33

9.

J.R.Hey: ``Practical Polyphase SSB for shallow pockets'' Radio Communication Sept 76, p656-660, 663

10.

J Heyne: ``New Active Quadrature Phase Shift Network'' IEE Electronics Letters, 31 March 1977, p216-218

11.

A G Constantinide: ``Digital Phase SPlitting Network Design for digital F.D.M. applications'' PROC IEE, Vol 23 No 12 Dec 1976, p 1313-1315

In addition, my comments on the op amp circuit are incorrect and should be ignored. Mike Gingell suggests doing away with the op amps altogether to get the best sideband suppression.