GB776098A - Improvements in or relating to frequency mixers - Google Patents

Abstract

776,098. Frequency charging circuits. TELEFONAKTIEBOLAGET L. M. ERICSSON. May 13, 1955 [May 4, 1954], No. 13958/55. Class 40(6) In a frequency changer having two non-linear elements fed with signal and local oscillations, a phase shifting device carrying both oscillations is arranged to connect the two elements so that signals fed to one element are phase shifted by 90 degrees with respect to the signal applied to the other. A signal is fed over line 5, Fig. 6 and local oscillations over line 7 to a diode 1 both oscillations also being fed down line 9 to a second diode 2. The output from the diodes 1, 2 are combined and fed to LF. discharge tube 17. The length of the line between the diodes 1, 2 is chosen to be one-quarter of a wavelength at the signal frequency and the line 9 is continued in a quarter-wave length stub. In a modification Fig. 7 (not shown) the local oscillation is applied to the diode 2 so that the output from diodes 1, 2 differ in phase by 180 degrees, and are combined in a transformer and fed to tube 17. In a modification, Fig. 8 the diodes 1, 2 are arranged in series, the D.C. path from diode 1 being completed over a stub 22 and the output from line 9 being taken through a further stub 21. A wave guide 23 may be employed, Fig. 9 matched by a stub 24 into a guide 9 having an admittance half that of the guide 23. The diodes 1, 2 may be arranged in series, Figs 10a (not shown). The signal and local oscillations are fed in through guide 23 but in a modification Fig. 11, local oscillation is fed in through guide 26, the outputs from diodes 1, 2 being out of phase and combined in transformer 19. For operation at lower frequencies, the signals are fed in over input 5, Fig. 15, filters 29, 30 producing a net phase shift of 90 degrees to the diodes 1, 2. In a modification Fig. 14 (not shown) only one filter is employed.