Self-tuning transmitter combiner comprising a plurality of filters combining with a reactive element at a junction and including a control unit for tuning the filters and reactive element
A self-tuning, resonant cavity transmitter combiner joins multiple RF transmitters and combines their signals onto a single transmission line. An additional tuning element is added to the junction of the signal paths to overcome the bandwidth limitations of the transmission lines joining the signal paths. An algorithm was developed to optimize the RF performance of the combiner by sampling the RF signals at various points in the RF circuit.
1 . A self-tuning transmitter combiner, the combiner comprising:
(a) a junction for combining a plurality of signals transmitted along a plurality of signal paths comprising a plurality of filters, respectively, the junction comprising a reactive element; and
(b) a computer-implemented control unit operable to tune the plurality of filters in response to a plurality of carrier frequencies of the plurality of signals, respectively, the control unit being further operable to tune the reactive element in response to a plurality of insertion gains respectively associated with the plurality of signal paths, said plurality of insertion gains comprising a lowest insertion gain, the reactive element being tuned such that said lowest insertion gain is maximized.
2 . The combiner of claim 1 wherein the control unit is operable to minimize a plurality of reflected powers of the plurality of filters by adjusting a plurality of tuning element positions associated with the plurality of filters, respectively.
3 . The combiner of claim 2 wherein the control unit is operable to determine, in response to a respective said carrier frequency, a corresponding said tuning element position by interpolation among a plurality of known tuning element positions respectively associated with a plurality of known carrier frequencies.
4 . The combiner of claim 1 wherein the reactive element has associated therewith a range of tuning positions, wherein the control unit is operable to set the reactive element to a midpoint tuning position of the range of tuning positions, and wherein the control unit is operable to then determine a first said lowest insertion gain.
5 . The combiner of claim 4 wherein the control unit is operable to determine a first said plurality of insertion gains associated with the plurality of signal paths respectively extending from a plurality of directional couplers of the combiner, through the plurality of filters, through the junction, and then to an output directional coupler of the combiner, said first plurality of insertion gains comprising said first lowest insertion gain, the control unit being further operable to then select said first lowest insertion gain from said first plurality of insertion gains.
6 . The combiner of claim 5 wherein the control unit is operable to:
(c) set the reactive element to a new tuning position of the reactive element, within the range of tuning positions, that is offset by a predetermined amount from a preceding tuning position of the range of tuning positions;
(d) determine a new said plurality of insertion gains in response to the new tuning position;
(e) determine a new said lowest insertion gain in response to said new plurality of insertion gains; and
(f) iteratively repeat steps (c) to (e) until said new lowest insertion gain is lower than a preceding said lowest insertion gain.
7 . A method of tuning a combiner, the method comprising:
(a) by a computer-implemented control unit, tuning a plurality of filters of a plurality of signal paths in response to a plurality of carrier frequencies of a plurality of signals being transmitted along the plurality of signal paths, respectively; and
(b) by the computer-implemented control unit, tuning a reactive element of a junction for combining the plurality of signals, the reactive element being tuned in response to a plurality of insertion gains respectively associated with the plurality of signal paths, said plurality of insertion gains comprising a lowest insertion gain, the reactive element being tuned such that said lowest insertion gain is maximized.
8 . The method of claim 7 wherein step (a) is performed before performing step (b), the method further comprising repeating step (a) after having performed step (b).
9 . The method of claim 8 wherein step (a) comprises minimizing a plurality of reflected powers of the plurality of filters by adjusting a plurality of tuning element positions of the plurality of filters, respectively.
10 . The method of claim 9 wherein adjusting the plurality of tuning element positions associated with the plurality of filters, respectively, comprises determining, in response to a respective carrier frequency of the plurality of carrier frequencies, a corresponding tuning element position of the plurality of tuning element positions by interpolating among a plurality of known tuning element positions respectively associated with a plurality of known carrier frequencies.
11 . The method of claim 10 further comprising repeating the step of respectively minimizing the plurality of reflected powers of the plurality of filters.
12 . The method of claim 8 wherein step (b) comprises setting the reactive element to a midpoint tuning position of a range of tuning positions of the reactive element and then determining a first said lowest insertion gain.
13 . The method of claim 12 wherein determining said first lowest insertion gain comprises determining a first said plurality of insertion gains associated with the plurality of signal paths extending from a plurality of input directional couplers of the combiner, through the plurality of filters, respectively, through the junction, and then to an output directional coupler of the combiner, said first plurality of insertion gains comprising said first lowest insertion gain, and further comprises selecting said first lowest insertion gain from said first plurality of insertion gains.
14 . The method of claim 13 further comprising setting the reactive element to a second tuning position, within the range of tuning positions, that is offset by a predetermined amount from the midpoint tuning position, and then determining a second said plurality of insertion gains associated with the plurality of signal paths, said second plurality of insertion gains comprising a second said lowest insertion gain, and then selecting said second lowest insertion gain from said second plurality of insertion gains.
15 . The method of claim 14 further comprising changing the polarity of the predetermined amount if said second lowest insertion gain is lower than said first lowest insertion gain.
16 . The method of claim 15 further comprising:
(c) setting the reactive element to a new tuning position, within the range of tuning positions, that is offset by the predetermined amount from a preceding tuning position of the range of tuning positions, the preceding tuning position having associated therewith a preceding said plurality of insertion gains comprising a preceding said lowest insertion gain;
(d) determining a new said plurality of insertion gains in response to the new tuning position, said new plurality of insertion gains comprising a new said lowest insertion gain;
(e) determining said new lowest insertion gain in response to said new plurality of insertion gains; and
(f) iteratively repeating steps (c) to (e) until said new lowest insertion gain is lower than said preceding lowest insertion gain.
17 . The method of claim 7 further comprising receiving, by the computer-implemented control unit, user instructions indicating manual override and, in response to the user instructions, performing at least one computer-implemented action selected from: (g) adjusting a tuning element position of a user-selected filter of the plurality of filters; and (h) setting the reactive element to a user-selected tuning position within a range of tuning positions of the reactive element.
18 . A self-tuning transmitter combiner, the combiner comprising:
(a) means for tuning a plurality of filters of a plurality of signal paths in response to a plurality of carrier frequencies of a plurality of signals being transmitted along the plurality of signal paths, respectively; and
(b) means for tuning a reactive element of a junction for combining the plurality of signals, the reactive element being tuned in response to a plurality of insertion gains respectively associated with the plurality of signal paths, said plurality of insertion gains comprising a lowest insertion gain, the reactive element being tuned such that said lowest insertion gain is maximized.