Unidirectional sampling mixer
View Patent ↗A unidirectional sampling mixer utilizes a stepped phase modulation to shift the frequency of an input signal. An RF input signal is supplied to an RF input switch from an RF input port. An ordered set of phase shift values to be applied to the RF input signal and a set of times each element of which correspond to a time at which a phase shift value is be applied to the RF signal are determined. For each phase shift value within the ordered set of phase shift values, a controller controls the RF input switch to select an input of a phase shifting device and controls an RF output switch to select an output of the phasing shifting device. The input of the phase shifting device and the output of the phase shifting device are selected to apply the phase shift value at its corresponding time to the RF input signal. A frequency shifted signal is supplied to an RF output port from an output of the RF output switch. This Abstract is not to be considered limiting, since other embodiments may deviate from the features described in this Abstract.
1. A method for shifting a frequency of a radio frequency (RF) signal in a selected direction, the method comprising:
supplying an RF input signal to an RF input switch from an RF input port;
determining an ordered set of phase shift values to be applied to the RF input signal;
determining a set of times each element of which correspond to a time at which a phase shift value is be applied to the RF signal;
for each phase shift value within the ordered set of phase shift values, controlling the RF input switch to select an input of a phase shifting device and controlling an RF output switch to select an output of the phasing shifting device, wherein the input of the phase shifting device and the output of the phase shifting device are selected to apply the phase shift value at its corresponding time to the RF input signal; and
supplying to an RF output port a frequency shifted signal from an output of the RF output switch.
2. The method of claim 1 , wherein the frequency shifted signal is higher in frequency than the RF input signal.
3. The method of claim 1 , wherein the frequency shifted signal is lower in frequency than the RF input signal.
4. The method of claim 1 , wherein the RF input signal is a modulated signal.
5. The method of claim 1 , wherein the phase shifting device is selected from the group consisting of a 90 degree hybrid, a 180 degree balun and a spatially-modulated antenna structure.
6. An apparatus to shift a frequency of a radio frequency (RF) signal in a selected direction, the apparatus comprising:
an RF input switch configured to receive an RF input signal from an RF input port;
a phase shifting device, wherein an output of the RF input switch is electrically connected to an input of the phase shifting device;
an RF output switch, wherein an input of the RF output switch is electrically connected to an output of the phase shifting device; and
a controller, wherein the controller is electrically connected to the first and second RF input switches and is configured to perform operations comprising:
receiving an ordered set of phase shift values to be applied to the RF input signal;
receiving a set of times each element of which correspond to a time at which a phase shift value is be applied to the RF signal; and
for each phase shift value within the ordered set of phase shift values, controlling the RF input switch to select an input of a phase shifting device and controlling an RF output switch to select an output of the phasing shifting device, wherein the input of the phase shifting device and the output of the phase shifting device are selected to apply the phase shift value at its corresponding time to the RF input signal,
wherein the RF output switch is configured to perform operations comprising:
receiving a frequency shifted signal from an output of the second phase shifting device; and
supplying the frequency shifted signal to an RF output port.
7. The apparatus of claim 6 , wherein the frequency shifted signal is higher in frequency than the RF input signal.
8. The apparatus of claim 6 , wherein the frequency shifted signal is lower in frequency than the RF input signal.
9. The apparatus of claim 6 , wherein the RF input signal is a modulated signal.
10. The apparatus of claim 6 , wherein the phase shifting device is selected from the group consisting of a 90 degree hybrid, a 180 degree balun and a spatially-modulated antenna structure.