System for processing patient monitoring signals
A patient monitoring signal processing system adaptively varies medical signal data rate. The system uses an analog to digital converter for digitizing an analog cyclically varying input signal derived from a patient in response to a sampling clock input. The sampling clock determines frequency of analog to digital sampling of the analog input signal by the analog to digital converter. A detector detects first and second different signal portions within a cycle of the cyclically varying input signal. A control processor coupled to the analog to digital converter and the detector, provides the sampling clock and adaptively determines first and second different frequencies of the sampling clock to be used in sampling within detected corresponding first and second different signal portions of the cyclically varying input signal in response to predetermined information indicating a frequency of a signal component of the cyclically varying input signal in the first signal portion is higher than a frequency of a signal component of the cyclically varying input signal in the second signal portion. Also the first frequency is higher than the second frequency of the first and second different frequencies.
1. A patient monitoring signal processing system for adaptively varying medical signal data rate, comprising:
an analog to digital converter for digitizing an analog cyclically varying input signal derived from a patient in response to a sampling clock input, said sampling clock determining frequency of analog to digital sampling of said analog input signal by said analog to digital converter;
a detector for detecting first and second different signal portions within a cycle of said cyclically varying input signal; and
a control processor coupled to said analog to digital converter and said detector, for providing said sampling clock and adaptively determining first and second different frequencies of said sampling clock to be used in sampling within detected corresponding first and second different signal portions of said cyclically varying input signal, the first frequency being higher than said second frequency of said first and second different frequencies in response to predetermined information indicating a frequency of a signal component of said cyclically varying input signal in the first signal portion is higher than a frequency of a signal component of said cyclically varying input signal in the second signal portion.
2. A system according to claim 1 , wherein
said control processor adaptively determines said first and second different frequencies of said sampling clock in response to a determination a frequency of a signal component of said cyclically varying input signal in the first signal portion is higher than a frequency of a signal component of said cyclically varying input signal in the second signal portion.
3. A system according to claim 1 , wherein
said first and second frequencies are fixed.
4. A system according to claim 1 , wherein
at least one of said first and second different frequencies is variable.
5. A system according to claim 3 , wherein
at least one of said first and second different frequencies is variable in response to a determined frequency content of said cyclically varying input signal.
6. A system according to claim 1 , including
a calculation processor for determining a maximum frequency of said cyclically varying input signal in at least one of said first and second different signal portions and selecting at least one of said first and second different frequencies in response to the maximum frequency determination.
7. A system according to claim 6 , wherein
said calculation processor selects at least one of said first and second different frequencies to be at least a two times multiple of a determined maximum frequency.
8. A system according to claim 1 , wherein
said control processor adaptively selects at least one of said first and second different frequencies to be zero and inhibits sampling during a corresponding first and second different signal portion.
9. A system according to claim 1 , wherein
said detector detects a third signal portion within said cycle of said cyclically varying input signal and
said control processor adaptively selects a frequency of said sampling clock to be zero in the third signal portion and inhibits sampling during the third signal portion.
10. A system according to claim 1 , including
a plurality of analog to digital converters for digitizing said analog cyclically varying input signal and
said control processor adaptively varies the number of said analog to digital converters used in sampling within detected corresponding first and second different signal portions of said cyclically varying input signal to increase sampling resolution in said first signal portion relative to said second signal portion.
11. A system according to claim 1 , wherein
said control processor adaptively determines said first and second different frequencies of said sampling clock in response to a determination a frequency of a signal component of said cyclically varying input signal in the first or second signal portions exceeds a predetermined frequency threshold.
12. A system according to claim 11 , wherein
said control processor adaptively determines said first and second different frequencies of said sampling clock in response to a determination a frequency of a signal component of said cyclically varying input signal in the first or second signal portions lies in a frequency range indicated using a look-up table.
13. A patient monitoring signal processing system for adaptively varying medical signal data rate, comprising:
an analog to digital converter for digitizing an analog cyclically varying input signal derived from a patient in response to a sampling clock input, said sampling clock determining frequency of analog to digital sampling of said analog input signal by said analog to digital converter;
a detector for detecting first and second different signal portions within a cycle of said cyclically varying input signal; and
a control processor coupled to said analog to digital converter and said detector, for providing said sampling clock and adaptively determining first and second different frequencies of said sampling clock to be used in sampling within detected corresponding first and second different signal portions of said cyclically varying input signal, the first frequency being higher than said second frequency of said first and second different frequencies in response to a control signal.
14. A system according to claim 13 , wherein
said control signal comprises predetermined information indicating a predetermined structure of said cyclically varying input signal.
15. A system according to claim 13 , wherein
said control signal comprises predetermined information indicating said first signal portion is of more interest than said second signal portion.
16. A patient monitoring signal processing system for adaptively varying medical signal data rate, comprising:
an analog to digital converter for digitizing an analog cyclically varying input signal derived from a patient in response to a sampling clock input, said sampling clock determining frequency of analog to digital sampling of said analog input signal by said analog to digital converter;
a detector for detecting first and second different signal portions within a cycle of said cyclically varying input signal; and
a control processor coupled to said analog to digital converter and said detector, for providing said sampling clock and adaptively determining first and second different frequencies of said sampling clock to be used in sampling within detected corresponding first and second different signal portions of said cyclically varying input signal, the first frequency being higher than said second frequency of said first and second different frequencies in response to a determination a frequency of a signal component of said cyclically varying input signal in the first signal portion is higher than a frequency of a signal component of said cyclically varying input signal in the second signal portion.
17. A patient monitoring signal processing system for adaptively varying medical signal data rate, comprising:
a plurality of analog to digital converters for digitizing an analog cyclically varying input signal derived from a patient in response to a sampling clock input, said sampling clock determining frequency of analog to digital sampling of said analog input signal by one or more of said plurality of analog to digital converters;
a detector for detecting first and second different signal portions within a cycle of said cyclically varying input signal; and
a control processor coupled to said analog to digital converter and said detector, for adaptively determining the number of said analog to digital converters used in sampling within detected corresponding first and second different signal portions of said cyclically varying input signal to increase sampling resolution in said first signal portion relative to said second signal portion in response to a control signal.
18. A system according to claim 17 , wherein
said control signal comprises predetermined information indicating a frequency of a signal component of said cyclically varying input signal in the first signal portion is higher than a frequency of a signal component of said cyclically varying input signal in the second signal portion.
19. A system according to claim 17 , wherein
said control processor generates said control signal by determining whether a frequency of a signal component of said cyclically varying input signal in the first signal portion is higher than a frequency of a signal component of said cyclically varying input signal in the second signal portion.