1. A system for the control of transmit power in a wireless communication device having a transmitter and a receiver, the receiver having a calibrated receiver signal pathway capable of determining the strength of a received signal, the system comprising:
a variable gain radio frequency (RF) transmitter amplifier having an amplifier input and an amplifier output and a variable gain control input, the variable gain control input initially receiving a control signal indicative of a desired transmit power level;
a mixer coupled to the amplifier output and receiving a local oscillator signal having an oscillator frequency corresponding to an operational frequency of the receiver, the mixer generating a signal at operational frequency of the receiver and corresponding to a signal at the amplifier output; and
a coupling circuit to couple the signal generated by the mixer to the receiver signal pathway to permit power measurement of the signal using the calibrated receiver signal pathway.
2. The system of claim 1, further comprising a linearizer containing linearization data indicative of a difference between the control signal indicative of the desired transmit power level and the power measured using the calibrated receiver signal pathway.
3. The system of claim 1 wherein the coupling circuit comprises a switch to couple the signal generated by the mixer to the receiver signal pathway.
4. The system of claim i wherein the receiver signal pathway comprises an intermediate frequency (IF) stage coupled to a demodulator stage, the coupling circuit coupling the signal generated by the mixer to the receiver signal pathway following the IF stage.
5. The system of claim 4, further comprising a bandpass filter intermediate the mixer and the coupling circuit to provide IF filtering.
6. The system of claim 1 wherein the oscillator frequency is selected to permit the signal generated by the mixer to match an intermediate frequency (IF) of the receiver.
7. The system of claim 1 wherein the coupling circuit comprises a single-pole-single-throw (SPST) type switch to couple the signal generated by the mixer to the receiver signal pathway
8. The system of claim 6 wherein the wireless communication device has a transmitter calibration mode, the coupling circuit being selected activated when in the transmitter calibration mode to permit the signal generated by the mixer to be coupled to the receiver signal pathway.
9. The system of claim 1 wherein the coupling circuit comprises a single-pole-double-throw (SPDT) type switch to couple the signal generated by the mixer to the receiver signal pathway.
10. The system of claim 9 wherein the receiver comprises a receiver variable gain amplifier in the receiver signal pathway, the SPDT type switch having a first terminal coupled to the output of the mixer to receiver the signal generated by the mixer, a second terminal coupled to a radio frequency (RF) stage of the receiver and a switch common terminal coupled to the receiver signal pathway.
11. The system of claim 10 wherein the second terminal is coupled to the RF stage via an intermediate frequency (IF) stage wherein the oscillator frequency is selected to permit the signal generated by the mixer to match an intermediate frequency (IF) of the receiver.
12. A method for the control of transmit power in a wireless communication device having a transmitter and a receiver, the receiver having a calibrated receiver signal pathway capable of determining the strength of a received signal, the method comprising:
setting a desired gain level of a variable gain radio frequency (RF) transmitter amplifier;
detecting an output of the variable gain transmitter amplifier indicating an actual gain level;
converting the frequency of the detected output to a frequency corresponding to an operational frequency of the receiver;
coupling the converted signal to the receiver signal pathway to permit power measurement of the signal using the calibrated receiver signal pathway.
13. The method of claim 12, further comprising determining linearization data indicative of a difference between the desired gain level and an actual gain level measured using the calibrated receiver signal pathway.
14. The method of claim 12 wherein the receiver signal pathway comprises an intermediate frequency (IF) stage coupled to a demodulator stage and coupling the converted signal to the receiver signal pathway comprises coupling the converted signal to the receiver signal pathway following the IF stage.
15. The method of claim 12 wherein converting the frequency of the detected output comprises converting the frequency of the detected output to match an intermediate frequency (IF) of the receiver.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A pressure sensor for measuring an external stress comprising:
a) a substrate having:
i) a bottom surface;
ii) a recess formed in the bottom surface of the substrate; and
iii) a top surface having a first area and a second area, the first area is located directly above the recess and the second area is located around the first area; and
b) an apparatus having a first resistor and a second resistor, the first resistor is located on the top surface of the substrate in the first area and the second resistor is located in the top surface of the substrate in the second area surrounding the first area,
wherein, when the pressure sensor is exposed to the external stress, the first resistor measuring the external stress by varying a first oscillating signal input into a first end of the first resistor and outputting a varied first oscillating signal from a second end thereof, and the second resistor receiving an input second oscillating signal in a first end thereof and outputting an output second oscillating signal from a second end thereof, the input second oscillating signal and the output second oscillating signal are unaffected by the external force.
2. A pressure sensor for measuring an external stress comprising:
a) a substrate having:
i) a bottom surface;
ii) a recess formed in the bottom surface of the substrate; and
iii) a top surface having a first area and a second area, the first area is located directly above the recess and the second area is located around the first area; and
b) an apparatus having a first resistor, a second resistor, and a third resistor, the third resistor is on the top surface of the substrate in a middle portion of the first area, the first resistor is located on the top surface of the substrate in the first area and spaced a predetermined distance from the third resistor, and the second resistor is located in the top surface of the substrate in the second area surrounding the first area,
wherein, when the pressure sensor is exposed to the external stress, the first resistor measuring the external stress by varying a first oscillating signal input into a first end of the first resistor and outputting a varied first oscillating signal from a second end thereof, the second resistor receiving an input second oscillating signal in a first end thereof and outputting an output second oscillating signal from a second end thereof, the input second oscillating signal and the output second oscillating signal are unaffected by the external force, the third resistor receiving an input third oscillating signal and outputting an output third oscillating signal decreasing as the external stress increases.