Variable code-tracking loop with improved signal dynamics, loop noise, and sensitivity
View Patent ↗A variable code-tracking loop filter in a receiver having the ability to change its parameters multiple times in response to received signals. Parameters for the code-tracking loop filter may be varied based on phase and frequency errors from an error detector. In one implementation, the code-tracking loop filter is able to repeatedly vary a single parameter, such as its received bandwidth, based on the phase and frequency errors, while in another, the code-tracking loop filter may vary two or more parameters, such as the loop bandwidth and the natural frequency.
1. A method for varying operating states of a variable code-tracking loop, comprising: generating, by a local signal generator, a local signal corresponding to a pseudo code; detecting at least one parameter of an error in the pseudo code between the local signal and an incoming signal; determining in a processor that a threshold has been reached by the at least one detected parameter of the error in the pseudo code between the local signal and an incoming signal; changing from a first operating state of the variable code-tracking loop to a second operating state in response to the threshold being reached; generating a correction signal in response to the at least one detected parameter; transmitting the correction signal to a the local signal generator; determining that the threshold is not reached; and reverting back to the first operating state from the second operating state upon the threshold not being reached.
2. The method of claim 1 , where determining further includes receiving a phase error as the at least one detected parameter.
3. The method of claim 1 , where determining further includes receiving a frequency error as the at least one detected parameter.
4. The method of claim 1 , where changing further includes:
operating at a first bandwidth in the first operating state; and
operating at a second bandwidth in the second operating state.
5. The method of claim 1 , further including the steps of:
generating an adjusted local signal at the local signal generator;
transmitting the adjusted local signal to an error detector; and
determining at least one additional detected parameter at the error detector utilizing the Input data and the adjusted local signal.
6. The method of claim 5 , further including the step of repeating the steps of claim 1 .
7. An apparatus for a variable code-tracking loop, comprising: means for generating a local signal corresponding to a pseudo code; means for detecting at least one parameter of an error in the pseudo code between the local signal and an incoming signal; means for determining in a processor that a threshold has been reached by the at least one detected parameter of the error in the pseudo code between the local signal and an incoming; means for changing from a first operating state of the variable code-tracking loop to a second operating state in response to the threshold being reached; means for generating a correction signal in response to the at least one detected parameter; means for transmitting the correction signal to a the means for generating the local signal; means for determining that the threshold is not reached; and means for reverting back to the first operating state from the second operating state upon the threshold not being reached.
8. The apparatus of claim 7 , further including means for receiving a phase error as the at least one detected parameter.
9. The apparatus of claim 7 , further including means for receiving a frequency error as the at least one detected parameter.
10. The apparatus of claim 7 , further including:
means for operating at a first bandwidth in the first operating state; and
means for operating at a second bandwidth in the second operating state.
11. The apparatus of claim 7 , further including:
means for generating an adjusted local signal at the local signal generator;
means for transmitting the adjusted local signal to an error detector; and
means for determining at least one additional detected parameter at the error detector utilizing the input data and the adjusted local signal.