Continuously variable electronically controlled phase shift circuit

A phase shift circuit for providing an output signal in response to an input signal to provide an adjustable shift of the phase of said input signal over a 360 degree range comprising:

• means responsive to an input signal for splitting the phase of said input signal into four separate signals that are equal in amplitude and 90 degrees out of phase with each other,
• an attenuation means responsive to said four separate signals for selectively attenuating at least one of said four separate signals in response to at least one applied control signal, said attenuation means including a first attenuating circuit means responsive to a first pair of said four separate signals from said splitting means, said first pair of said signals being 180 degrees out of phase with each other, for selectively attenuating one of said first pair of signals in response to a first control signal applied to said first attenuation circuit means, and a second attenuation circuit means responsive to a second pair of said four separate signals from said splitting means, said second pair of signals being 180 degrees of out phase with each other, for selectively attenuating one of said second pair of signals in response to a second control signal applied to said second attenuation circuit means,
• a combining means for combining said signals from said attenuation means into a single output signal having a phase shift determined by the amount of attenuation of said at least one of said separate signals with respect to the other ones of said four separate signals, said single output signal having a resultant phase that is phase shifted with respect to said input signal by a selected amount of phase within a 360 degree range as determined by said amount of attenuation,
• wherein said combining means includes a first combining circuit means for combining said first pair of signals from said first attenuation circuit means into one signal having a phase shift determined by the amount of attenuation of said attenuated one of said first pair of signals with respect to the unattenuated one of said pairs of signal,
• a second combining circuit means for combining said second pair of signals from said second attenuation circuit means into one signal having a phase shift determined by the amount of attenuation of said attenuated one of said second pair of signals with respect to the unattenuated one of said pair of signals,
• and a third combining circuit means responsive to said output signals from said first and second combining means for combining said signals therefrom into said single output signal having a resultant phase that is phase shifted with respect to said input signal by a selected amount of phase within a 360 degree range as determined by said amounts of attenuation,
• wherein said phase splitting means includes a capacitance element responsive to said input signal to said phase shift circuit for providing an output signal on a first output lead, and an inductance element responsive to said input signal to said phase shift circuit for providing an output signal on a second output lead, said output signals on said first and second output leads being 90 degrees apart in phase.