1.       Original Patents on Polyphase networks –

1.1.                M.J.Gingell: "A Symmetrical Polyphase Network",

1.1.1.                    British Patents 1,174,709 & 1,174,710, published 17 Dec 1969,

1.1.2.                    US Patents 3,559,042 & 3,618,133 published Jan 26 1971.

1.2.                British Patent office

1.3.                US patent office


2.       One of the first publications about Polyphase networks I could find. –

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


3.       The publication of C.L. Fortesque deals with N phase phasor systems where N is a positive integer. His work is mostly used for analyzing 3 phase AC power systems. M.J. Gingell used it in 2.1 to show that a set of 4 phasors can be represented by 4 sets of symmetrical phasors. In Polyphase SSB circuits only two phasor systems are used. The other systems have a zero amplitude and so are not present.

3.1.                C.L. Fortesque: “Method of Symmetrical Co-Ordinates Applied to the Solution of Polyphase Networks”, 34th Annual convention of the American Institute of Electrical Engineers, Atlantic City, N.J. June 28, 1918

3.2.                Tim Skaverina: Symmetrical Components Lectures.


4.       Pat Hawker, G3VA picked up the above article and mentioned it several times in his 'Technical Topics' column in the Radio Communication magazine of the RSGB -

4.1.                "Polyphase System for SSB Generation", Radio Communication Oct 73, p698-699

4.2.                Peter Martinez, G3PLX" More on Polyphase SSB", Radio Communication Dec 73, p852-853

4.3.                "Peter Martinez, G3PLX Polyphase SSB generator", Radio Communication May 1975, p379-381


5.       HA5WH showed how to use a Polyphase network in a SSB demodulator, exciter and clipper. This circuit appeared later in many ARRL handbook editions. It is unfortunate that sub optimum component values are listed and that the insensitivity to component tolerance for high performance networks is overestimated –

5.1.                Dr. A. Gschwindt, HA5WH, “Some Reflections on the Four-Way Phasing Method”, Radio Communication, January 1976


6.       John Hey, G3TDZ, published a  SSB exciter in an article in Radio Communication -

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


7.       I wrote a thesis as part of my Engineering study. It contains a program to design a Polyphase network and off course I  build one. Because all of it is in Dutch it is off little use to scan in the text –

7.1.                W.J. Niessen, Enkelzijband modulatie met behulp van een Polyfase netwerk. Gemeentelijke HTS Utrecht 1977-1978

7.2.                1978 Vintage Polyphase exciter pictures.


8.       Two phase and Polyphase SSB systems are discussed in this article. Polyphase systems are claimed to cancel the unwanted sideband inside the Polyphase network. I (still) view a Polyphase system as a “balanced” form of a Two phase system. Granted, a Polyphase network has some nice “error correction features” not found in all-pass networks but both systems in the end use quadrature AF and RF signals which get multiplied and added.  In this multiply and add process the unwanted sideband gets suppressed and not inside the Polyphase network. (So I’ve been trying for some time to get a copy of this article. So far without success. Anybody who can help?

8.1.                Dr. R.C.V. Macario, GW8SRW, and I.D. Mejallie, ‘The Phasing Method for Sideband Selection in Broadcast Receivers’, EBU Review, June 1980


9.       I ported my 1978 program to an ATARI ST and build a simple circuit to compare  capacitor’s with better then 0.1% accuracy. Dick Rollema, PA0SE, mentioned this in his monthly column ‘Reflecties door PA0SE’ in Electron, the journal of one of the Dutch Radio Amateur organisations. Using this program I found that the insertion loss of a Polyphase network depends on the signal direction through the network -.

9.1.                Dick Rollema, PA0SE: “Refelecties door PA0SE, PEoPIM verbetert polyfase netwerk”, Electron, December 1990, pag. 652-654, (Dutch language)


10.   An analysis of the Polyhase network. Most of the mathematics Kevin Schmidt uses is beyond me. Fortran program’s are included –

10.1.            Schmidt Kevin (W9CF): "Phase-Shift Network Analysis and Optimization", QEX, 1994, April, pp 17-23


11.   A method to design a Polyphase network with 0dB insertion loss. Impedances get high and Capacitor values small so take care of parasitic- and stray Capacitance when building one of these –

11.1.         Yoshida, Tetsuo (JA1KO), "Polyphase Network Calculation using a Vector Analysis Method", QEX, 1995, June, pp 9-15


12.   A SSB receiver with continuous variable bandwith and an excellent shape factor. It uses Polyphase networks in both the RF and audio path.

12.1.             Rodney Green, (VK6KRG), "The Bedford Receiver: A New Approach", QEX, 1999, Sept/Oct, pp 9-23


13.   A receiver using a Commutating Detector and Polyphase network. On the internet there is a spreadsheet allowing you to design a Polyphase network. I later used the layout idea of this spreadsheet to write my own Macro, see 17.2 below .

13.1.            Jan Verduyn, G0BBL, Steve, G0XAR, Alan, G7PUB, “The QRP2001”, ‘Sprat no. 101’ Winter 1999/2000


14.   Harold Wilson, G3OGW, started working on Polyphase networks and moved on to include a quadrature demodulator. Pat Hawker gives an overview of Publications and reports on Wilson’s work –

14.1.            "Polyphase SSB Detector for D-C Receivers" in ‘Technical Topics’ in Radio Communication, April 2001, pp 62-64, reprinted in ‘Technical Topics Scrapbook’ 2000-2004, pp 70-72

14.2.            "G3OGW's 4-Path Polyphase D-C Receiver" in "Technical Topics" In Radio Communication, May 2001, pp 61-62, reprinted in ‘Technical Topics Scrapbook’ 2000-2004, pp 73-74

14.3.            "More on Polyphase Filters" in "Technical Topics" in RSGB Radio Communications, June 2001, pp 61-63. Reprinted in ‘Technical Topics Scrapbook’ 2000-2004, pp 77-79.


15.   Michael Gingell, KN4BS, Jan Verduyn, G0BBL and Graham Rogers, G3TFL, provided information to Pat Hawker. G0BBL presents a novel circuit to provide Quadrature RF signals. It requires an oscillator at twice the final frequency. Conventional circuits require an oscillator at four times the final frequency. (Note: The 74HC86 in the diagram are eXclusive OR gates not NOR gates as drawn.). G3TFL presents an 8 segment Polyphase network using identical Capacitors in each segment.

15.1.            “More on 4-Path Polyphase” in "Technical Topics" in RSGB Radio Communications, July 2001, pp xx-xx. Reprinted in ‘Technical Topics Scrapbook’ 2000-2004, pp 81‑83.


16.   Maxim published an Application note for their MAX2452 chip which contains two Multipliers, and an Oscillator followed by a Quadrature circuit. Together with some Op-Amps and a Polyphase network a low power SSB exciter is presented. Note: C6 =100 nF is the wrong value. 3.9 nF is better.


17.   Peter Martinez, G3PLX, did an excellent job in summarizing the functioning of a Polyphase network, see 4.2 above. But, it left me with the question of why does it work this way.  The mathematics Kevin Schmidt uses, see 10 above, is a bit too much for me. So I went back to my 1978 work and wrote up how a Polyphase network functions using rather elementary electronic theory. Using my 1978/1990 Polyphase network design program I included also a Spreadsheet allowing you to quickly optimize a network design. Apart from Unwanted Sideband Suppression it also plots Insertion loss, Zin and Zout. A number of guidelines on how to implement Polyphase networks are included. The most important one is that for a Polyphase network with equal Capacitors the insertion loss depends on the signal direction through the network. Contrary to “gut feeling” the segment with the lowest RC frequency must be at the output for minimum insertion loss.

17.1.            Understanding_and_designing_Polyphase_networks

17.2.            Excel spreadsheet and Macro for designing a Polyphase network


18.   János Ladvánszky and Gerhard Schultes of Austria Microsystems wrote an article on the Noise Figure Minimization of Polyphase Filters when used to generate quadrature IF signals. They optimize the noise figure but there is no mentioning of the effect on the Insertion loss when doing this. For audio applications there work does not seem to be applicable because over a decade of frequency  in- and output impedances vary drastic. Still interesting reading material.

18.1.            www.austriamicrosystems.com


19.   A receiver using a Polyphase network.

19.1.            www.hanssummers.com/radio/polyphase/index.htm


20.    Three Band Receiver using a Tayloe Detector and a Polyphase network designed and build by Jean Taeymans. Jean  made an equal Capacitor Polyphase network. After suggesting to “reverse” the network he gained 10 dB for free. His Website lists all the constructional details, source code, pcb layout, schematics, etc.

20.1.            Three Band Receiver .


21.   Matti Hohtola (OH7SV) and Juha Niinikoski (OH2NLT) are building an all-band transceiver. It uses a Commutating detector/mixer, DDS, Polyphase networks, audio filters, advanced Power FET PA design, etc. Most of it is done using SMD components. Matti provided me with the data of his audio filter so I could optimize my design of a Polyphase network using a bag of 1% Capacitors donated to me.

21.1.            Direct Conversion HF transceiver with DDS Local Oscillator.



Other useful links when working with Polyphase networks.


22.    Almost All Digital Electronics produces a very nice LC meter based on a PIC processor. It is available in kit form or ready build. Apart from absolute measurements it also has a “Match mode” where it will report the difference to a reference component, both in absolute and percentage numbers. This feature is quite useful when selecting Capacitors for a Polyphase network. Components are getting smaller and smaller. Also the readability of the printing on them is going down as well. I should have bought one years ago!


22.1.            http://www.aade.com/lcmeter.htm


23.   Experimental Methods in RF Design, ARRL ISBN # 0-87259-879-9 is an excellent book full of ideas. In chapter 9 Rick Campbell, discusses the inns and out’s of direct conversion and phasing equipment and presents the R2Pro. Rick favours all pass networks over Polyphase networks so the only get briefly mentioned.