H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
H03D7/06—Transference of modulation from one carrier to another, e.g. frequency-changing by means of discharge tubes having more than two electrodes
H03D7/08—Transference of modulation from one carrier to another, e.g. frequency-changing by means of discharge tubes having more than two electrodes the signals to be mixed being applied between the same two electrodes