| 摘要 |
An apparatus for producing a single side band at systems where a signal of a certain frequency is received, frequency-shifted and reflected. The apparatus comprises a modulator (b 26), which includes only one diode (44). To the diode are applied a series of different voltage levels generated in a commutator circuit (41), which voltage levels are at least three in number. A tuning circuit (45) is provided between the diode and an aerial (25). The tuning circuit (45) is adjusted to act upon the amplitude and phase variations occurring at the diode (44) at the different voltage levels applied, so that the reflection coefficients of the diode (44) and the characteristics of the tuning circuit (45) together satisfy the condition for a single side band to be formed and transmitted from the aerial (25). |
