Patent attributes
A phase shifting device includes a signal source; a variable phase shifter; first and second doubling circuits; and a 90-degree phase comparator. An output from the signal source is connected to an input of the variable phase shifter and to an input of the second doubling circuit, an output from the variable phase shifter is connected to an input of the first doubling circuit, an output from the first doubling circuit serves as a first output signal, and an output from the second doubling circuit serves as a second output signal. The first output signal and the second output signal are inputted to the 90-degree phase comparator. The amount of phase shift rotation of the variable phase shifter is changed by a phase shift control signal outputted from the 90-degree phase comparator. By this, an exact 90-degree phase shift is obtained.
