Multi-channel RX/TX calibration and local oscillator mismatch mitigation
A method and system of optimizing transmit beam forming in a multiple radio wireless system is provided. A stimulus signal can be provided to an analog receive input of a device under test (DUT), wherein the DUT includes multiple radios. A receive phase and amplitude can be measured at baseband using the stimulus signal for each radio. At this point, a receive weight and its conjugate can be determined using the receive phases and amplitudes. A calibration vector and its conjugate can also be determined, wherein a product of the receive weight conjugate and the calibration vector conjugate generate a transmit weight. This transmit weight can be applied to transmit signals during the transmit beam forming using the multiple radios.
1. A shunt switch for a multiple radio wireless system, the shunt switch comprising:
a first capacitor connected between a first antenna path, which is associated with a first antenna, and a first node;
a diode having an anode connected to the first node and a cathode connected to a second antenna path, which is associated with a second antenna, separate from the first antenna;
a first inductor connected between the cathode of the diode and ground;
a first resistor connected between a control signal terminal and a second node;
a second inductor connected between the second node and the first node;
a second capacitor connected between the second node and ground;
a third capacitor coupled between the first node and radio receiver components of a first radio;
a controller in electrical communication with the control signal terminal and configured to selectively bias the diode to switch between a first electrical path and a second electrical path such that the first radio and a second radio receive a common signal to facilitate measuring a receive phase difference between the first and second radios.
2. The shunt switch of claim 1 , further including: a second resistor connected between the first node and the third capacitor; a fourth capacitor connected between the control signal terminal and ground; and a fifth capacitor connected between the first node and ground.
3. The shunt switch of claim 1 , wherein the first electrical path connects the radio receiver components of the first radio with the first antenna path.
4. The shunt switch of claim 1 , wherein the second electrical path connects the radio receiver components of the first radio with the second antenna path.