2 DAMGOV, V.N.: 'Design and application of negative R, C and Ltwo-poles based on four-frequency parametric systems'. Proceedingsof 1982 IEEE International Symposium on circuits and systems,Rome, May 10th-12th 1982, pp. 190-193

3 WEISHTEIN, L.A., and DUBOSHINSKY, J.B.: 'About the low-frequency oscillations under the action of high-frequency forces', J.Tech. Phys., 1978, 48, pp. 1321-1325

4 PRENTZLAU, N.N., DMITRIEV, V.M., and BOBRYCHEV, V.D.:'Microwave field-induced generation of low-frequency oscillations bysemiconductor diodes', Radiotekh. & Elektron., 1979, 24, pp. 1702-1704

5 GONDA, J.: 'IMPATT diode circuit design for parametric stability',IEEE Trans., 1977, MTT-25, pp. 343-352

6 ROMANJUK, V.A., and SHARIFOV, G.M.: Parasitic oscillations ina VHF oscillator utilizing active one-ports', Radiotekh. (USSR), 1977,32, pp, 57-63

7 LICHAREV, K.K., and ULRISH, B.G.: 'Systems with Josephsoncontacts'. Moscow University, Moscow 1978

8 SAMOYLO, K.A.: 'A method for analysis of oscillating systems ofsecond order' ('Sov. Radio', Moscow, 1976

9 SPASOV, A.Y., ENIKOVA, A.I., and ANGELOV, I.M.: 'On the cal-culation of harmonic oscillators utilizing negative resistance', Int. J.Electron., 1972,32, pp. 687-695

10 BRAGINSKY, V.B., and MANUKIN, A.B.: 'Alteration of smallforces in physical experiments' ('Nauka', Moscow, 1974)

11 HOTHUNZEV, YU.L., and TAMARCHAK, D.Y.: 'Injection-lockedoscillators and doppler radars with self-detecting oscillators usingsemi-conductor devices' ('Radio i Sviaz', Moscow, 1982)

12 TAMARCHAK, D.Y., and HOTUNZEV, YU.L.: 'Frequency conver-sion in a self-oscillating systems', Izv. VUZ Radioelektron., 1978, 21,pp. 58-64

13 GUPTA, M.S., LOMAX, R.J., and H ADD AD, G.: 'Noise consider-ation in self-mixing IMPATT-diode oscillators for short rangedoppler radar applications, IEEE Trans., 1974, MTT-22, pp. 37—43

Vladimir N. Damgov was born on 22ndNovember 1947, in Sofia, Bulgaria. Hereceived the Dipl.-Eng. degree in electricalengineering from the Moscow EnergeticInstitute and the Ph.D. degree in physicsand mathematics in 1977 from MoscowState University, 'M.V. Lomonossov',Moscow, USSR.

Since 1971 he has been a scientificworker in the Institute of Electronics of theBulgarian Academy of Sciences, Sofia 1184,

Bulgaria. His special interests are nonlinear and parametric phe-nomena, and radiophysical aspects of synergetics. He is aMember of Union of Bulgarian Scientific Workers.

ErratumBRUTON, L.T., STRECKER, T.E.: 'Two-dimensional dis-crete filters using spatial integrators', IEE Proc. G, Elec-tron. Circuits & Syst., 1983, 130, (6), pp. 271-275.

The second summation on the top right-hand side ofp. 272 should be

n- 1

s{m, n) = X r(m, j)

The subcaptions to Figs 4A and 4B should bev(m, n) = u(m — 1, n) + v(m — 1, n) and s(m, n) =r(m, n — I) + s{m, n — 1), respectively

The following corrections to Table 1 should be made:For numerator coefficients of akl

for k = 0 and / = 1 entry should be 0.19233994537 x 10" 7

for k = 2 and / = 1 entry should be0.192339945376 x 10"6

for k = 4 and / = 0 entry should be0.192339945376 x 10"7

For denominator coefficients of bkl

All the exponents should be positive

The following corrections to Table 2 should be made:For denominator coefficients of bkl

for k = 0 and / = 0 entry should be0.100000000000 x 10+ 1

for k = 1 and / = 1 entry should be0.107343056060 x 10+ 1

The phrase before eqn. 7 on p. 274 should be '. . . the frac-tional change of gain is'

The right-hand side of eqn. 12 on p. 274 should be

Re < .m r— > Abkl

ETC 107G

IEE PROCEEDINGS, Vol. 131, Pt. G, No. 1, FEBRUARY 1984