Systems and methods for synching a host computer with a variety of external devices
A method of calculating the difference between a device clock and a host clock over a communication network is provided. In a preferred embodiment, the method comprises: a.) sending a sync requests over the communication network; b.) storing in memory a sent host time T H 0 when the sync requests was sent; c.) receiving a local time report over a communication network from a local device; d.) storing in memory a device local time X extracted from the local time report; e.) storing in memory a receive host time T H 3 when the local time report was received; f.) calculating T such that T=(T H 0+T H 3)/2; repeating steps a through f a plurality of times; and calculating coefficients Ai and Bi using linear regression after repeating steps a through f at least twice where X=Ai*T+Bi.
1. A method of syncing a device clock over a communication network comprising:
sending a plurality of sync requests over the communication network;
for each sync request, storing in memory a sent host time T H 0 when the sync request was sent;
receiving from a local device a plurality of local time reports over the communication network;
for each local time report, storing in memory a receive host time T H 3 when the local time report was received;
calculating T such that T=(T H 0+T H 3)/2 for a plurality of sent host times and their corresponding receive host times;
for each local time report, storing in memory a device local time X extracted from the local time report; and
calculating coefficients Ai and Bi using linear regression after calculating T from at least two host times and their corresponding receive host times where X=Ai*T+Bi.
2. The method of claim 1 , further comprising the step of sending coefficients Ai and Bi to the local device.
3. The method of claim 1 , further comprising the step of calculating a time on the local device from a host time by multiplying the host time by Ai and adding Bi.
4. The method of claim 1 , further comprising the step of calculating a host time by taking a local device time and subtracting Bi and dividing the result by Ai.
5. The method of claim 1 , wherein the device local time is measured in CPU ticks.
6. The method of claim 1 , wherein the device local time is measured in seconds.
7. The method of claim 1 , wherein the linear regression is least squares.
8. The method of claim 1 , further comprising applying a filter to Ai and Bi to reduce the noise.
9. The method of claim 8 , wherein the filter is a low pass filter.
10. A method of syncing a device clock over a communication network comprising:
a.) sending a sync requests over the communication network;
b.) storing in memory a sent host time T H 0 when the sync requests was sent;
c.) receiving a local time report over a communication network from a local device;
d.) storing in memory a device local time X extracted from the local time report;
e.) storing in memory a receive host time T H 3 when the local time report was received;
f.) calculating T such that T=(T H 0+T H 3)/2;
repeating steps a through f a plurality of times; and
calculating coefficients Ai and Bi using linear regression after repeating steps a through f at least twice where X=Ai*T+Bi.
11. The method of claim 10 , further comprising the step of sending coefficients Ai and Bi to the local device.
12. The method of claim 10 , further comprising the step of calculating a time on the local device from a host time by multiplying the host time by Ai and adding Bi.
13. The method of claim 10 , further comprising the step of calculating a host time by taking a local device time and subtracting Bi and dividing the result by Ai.
14. The method of claim 10 , wherein the device local time is measured in CPU ticks.
15. The method of claim 10 , wherein the device local time is measured in seconds.
16. The method of claim 10 , wherein the linear regression is least squares.
17. The method of claim 10 , further comprising applying a filter to Ai and Bi to reduce the noise.
18. The method of claim 17 , wherein the filter is a low pass filter.