Apparatus and method for measuring the level of RF signals, and a transmitter including a wide band measurement circuit
First Claim
Patent Images
1. An apparatus, comprising:
- a radio frequency signal path,as a part of said radio frequency signal path a transmission phase shifter,a measurement circuit,a first coupling between a first end of said transmission phase shifter and the measurement circuit,a second coupling between a second end of said transmission phase shifter and the measurement circuit, andas a part of said second coupling a first phase shifter dimensioned to produce a phase shift of same magnitude as said transmission phase shifter;
wherein the measurement circuit is configured to combine a signal coming through said second coupling with a phase-inverted version of a signal coming through said first coupling to produce a first output signal indicative of a power level of a first radio frequency signal on said radio frequency signal path.
4 Assignments
0 Petitions
Accused Products
Abstract
On a radio frequency signal path a transmission phase shifter causes a phase shift. From a first end of said phase shifter comes a first sample, and from a second end of said phase shifter comes a second sample. Another phase shifter changes the phase of the second sample by the same magnitude as said transmission phase shifter. A measurement circuit combines the phase-shifted second sample with a phase-inverted version of the first sample to produce an output indicative of a power level of the original signal on the radio frequency signal path.
-
Citations
22 Claims
-
1. An apparatus, comprising:
-
a radio frequency signal path, as a part of said radio frequency signal path a transmission phase shifter, a measurement circuit, a first coupling between a first end of said transmission phase shifter and the measurement circuit, a second coupling between a second end of said transmission phase shifter and the measurement circuit, and as a part of said second coupling a first phase shifter dimensioned to produce a phase shift of same magnitude as said transmission phase shifter; wherein the measurement circuit is configured to combine a signal coming through said second coupling with a phase-inverted version of a signal coming through said first coupling to produce a first output signal indicative of a power level of a first radio frequency signal on said radio frequency signal path. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
and wherein the measurement circuit is configured to combine a signal coming through said third coupling with a phase-inverted version of a signal coming through said fourth coupling to produce a second output signal indicative of a power level of a second radio frequency signal on said radio frequency signal path.
-
-
9. An apparatus according to claim 8, wherein the transmission phase shifter is an antenna signal transmission line having an electrical length and configured to conduct radio frequency signals on their way towards an antenna of a communications device, and said second phase shifter is a transmission line having an electrical length equal to the electrical length of said antenna signal transmission line.
-
10. An apparatus according to claim 8, wherein the measurement circuit comprises a third differential amplifier having a non-inverting input and an inverting input, and wherein said third coupling is coupled to said non-inverting input and said fourth coupling is coupled to said inverting input, and wherein an output of said second differential amplifier is configured to deliver said second output signal.
-
11. An apparatus according to claim 8, wherein:
-
the measurement circuit comprises a third amplifier having an unbalanced input and a balanced output with a positive output port and a negative output port, the measurement circuit comprises a fourth amplifier having an unbalanced input and a balanced output with a positive output port and a negative output port, said third coupling is coupled to said unbalanced input of said third amplifier and said fourth coupling is coupled to said unbalanced input of said fourth amplifier, and the measurement circuit is configured to produce a third combined signal as a combination of signals from the positive output port of said third amplifier and signals from the negative output port of said fourth amplifier, the measurement circuit is configured to produce a fourth combined signal as a combination of signals from the negative output port of said third amplifier and signals from the positive output terminal of said fourth amplifier, and said second output signal is a voltage between said third and fourth combined signals.
-
-
12. An apparatus according to claim 8, wherein the measurement circuit comprises one or more control inputs, and wherein the measurement circuit is configured to respond to a calibration signal brought to a control input by changing a balance between a signal coming through said fourth coupling and a signal coming through said third coupling.
-
13. An apparatus according to claim 12, wherein the measurement circuit comprises a controllable amplifier, and wherein at least one of said one or more control inputs is a bias input to said controllable amplifier.
-
14. An apparatus according to claim 12, wherein the measurement circuit comprises a programmable attenuator coupled to said fourth coupling and said third coupling, and wherein at least one of said control inputs is a control input of said programmable attenuator.
-
15. A communications device, comprising:
-
a first radio frequency signal path, as a part of said first radio frequency signal path a first transmission phase shifter, a second radio frequency signal path, as a part of said second radio frequency signal path a second transmission phase shifter dimensioned to produce a phase shift of same magnitude as said first transmission phase shifter, a measurement circuit, a first coupling between a first end of said first transmission phase shifter and the measurement circuit, a second coupling between a second end of said first transmission phase shifter and the measurement circuit, as a part of said second coupling a first phase shifter dimensioned to produce a phase shift of same magnitude as any of said first and second transmission phase shifters, a third coupling between the first end of said first transmission phase shifter and a first end of said second transmission phase shifter, said third coupling having an electrical length, and a fourth coupling between the second end of said first transmission phase shifter and a second end of said second transmission phase shifter, said fourth coupling having an electrical length equal to the electrical length of said third coupling; wherein the measurement circuit is configured to combine a signal coming through said second coupling with a phase-inverted version of a signal coming through said first coupling to produce a first output signal indicative of a power level of a first radio frequency signal on one of said first and second radio frequency signal paths. - View Dependent Claims (16, 17, 18)
and wherein the measurement circuit is configured to combine a signal coming through said fifth coupling with a phase-inverted version of a signal coming through said sixth coupling to produce a second output signal indicative of a power level of a second radio frequency signal on one of said first and second radio frequency signal paths.
-
-
17. A communications device according to claim 15, wherein:
-
the communications device comprises a control block, the measurement circuit comprises one or more control inputs, and the measurement circuit is configured to respond to a calibration signal brought from said control block to a control input by changing a balance between a signal coming through said second coupling and a signal coming through said first coupling.
-
-
18. A communications device according to claim 17, wherein said control block is configured to store a number of frequency-specific calibration signal values for calibrating the operation of the measurement circuit depending on a frequency of the radio frequency signal on one of said first and second radio frequency signal paths.
-
19. A chipset for use in a communications device, comprising:
-
a measurement circuit, a first coupling between a first end of a transmission phase shifter and the measurement circuit, a second coupling between a second end of said transmission phase shifter and the measurement circuit, as a part of said second coupling, connections to a first phase shifter dimensioned to produce a phase shift of same magnitude as said transmission phase shifter; wherein the measurement circuit is configured to combine a signal coming through said second coupling with a phase-inverted version of a signal coming through said first coupling to produce a first output signal indicative of a power level of a first radio frequency signal going through said transmission phase shifter. - View Dependent Claims (20)
-
-
21. A method, comprising:
-
sampling a radio frequency signal to produce a first sampled version of the radio frequency signal, phase-shifting said radio frequency signal and sampling the phase-shifted radio frequency signal to produce a second sampled version of the phase-shifted radio frequency signal, replicating the phase-shifting of said radio frequency signal for said second sampled version, thus producing a phase-shifted second sampled version, and combining said phase-shifted second sampled version with a phase-inverted version of said first sampled version of the radio frequency signal, to produce a first output signal indicative of a power level of said radio frequency signal. - View Dependent Claims (22)
-
Specification