1. A clock translator, comprising:
a first input to receive a first reference clock signal;
a second input to receive a second reference clock signal;
an output to provide a bit rate clock signal having a clock frequency in a first ratio with respect to the frequency of the first reference clock but having a resolution based on at least a portion of the second reference clock signal.
2. The clock translator of claim 1, wherein the rate of the first reference clock signal is asynchronous with respect to the second clock signal.
3. The clock translator of claim 1, wherein the bit rate clock signal includes a plurality of pulses, and wherein the plurality of pulses have a frequency in a first ratio with respect to the frequency of the first reference clock signal and wherein a first set of the plurality of pulses are synchronized with edge transitions of the second reference clock signal.
4. The clock translator of claim 1, wherein the second reference clock signal is at a faster rate than the first reference clock signal.
5. The clock translator of claim 1, wherein the bit rate clock signal is provided to a parallel to serial converter.
6. The clock translator of claim 1, further comprising:
a third input to receive a sample rate control input, wherein the first ratio is controlled by the sample rate control input.
7. The clock translator of claim 6, wherein the sample rate control input is a sample rate control input of a sample rate converter.
8. The clock translator of claim 6, wherein the sample rate control input is provided by a digital phase lock loop.
9. The clock translator of claim 6, further comprising:
a first translation stage to calculate a second ratio between a rate of the second reference clock and a rate of the first reference clock;
a second translation stage responsive to the first translation stage to provide the bit rate clock signal based on the sample rate control input.
10. The clock translator of claim 9, wherein the first translation stage includes an input module responsive to the first clock signal and a low pass filter responsive to the input module.
11. The clock translator of claim 10, wherein the low pass filter comprises an integrator, a feed forward value, and wherein the magnitude of the feed forward value is substantially subtracted from the integrator.
12. The clock translator of claim 9, wherein the second translation stage includes a delta-sigma modulator responsive to the sample rate control input.
13. The clock translator of claim 12, wherein the second translation stage comprises an accumulator responsive to the first translation stage, a comparator responsive to the accumulator and to a reference value, wherein the accumulator is further responsive to the sample rate control input when the comparator indicates a favorable condition of the accumulator with respect to the reference value.
14. The clock translator of claim 13, wherein the reference value is zero.
15. A parallel to serial conversion system, comprising:
a sample rate converter to convert the sample rate of a digital input signal based on a sample rate control input;
a parallel to serial converter responsive to the sample rate converter to convert a parallel input to a serial output based on a bit clock rate; and
a clock translator, including:
a first input to receive the sample rate control input;
a second input to receive a first reference clock signal;
a third input to receive a second reference clock signal;
an output to provide the bit rate clock signal having a clock frequency in a first ratio with respect to the frequency of the first reference clock but having a resolution based on at least a portion of the second reference clock signal.
16. The parallel to serial conversion system of claim 15, further comprising:
a digital phase lock loop to provide the sample rate control input based on the first reference clock signal.
17. The parallel to serial conversion system of claim 15, wherein the sample rate control input includes an integer portion and a fractional portion.
18. The parallel to serial conversion system of claim 15, wherein the clock translator further includes an input module responsive to the first reference clock, an integrator responsive to the input module, and a delta-sigma modulator responsive to the integrator.
19. The parallel to serial conversion system of claim 18, wherein the delta-sigma modulator is responsive to the sample rate control input.
20. A method of providing a bit stream signal, the method comprising:
generating a bit stream signal having a plurality of bit transitions, wherein the plurality of bit transitions have a frequency in a first ratio with respect to the frequency of a first clock signal wherein a first set of the plurality of bit transitions have timing that is derived based on edges of a second clock signal; and
providing the generated bit stream signal.
21. The method of claim 20, wherein the second clock signal has a faster rate than and is asynchronous with respect to the first clock signal.
22. The method of claim 20, further comprising:
calculating a ratio between a rate of the second clock signal and a rate of the first clock signal; and
generating the bit stream signal based on the ratio and based on a sample rate control input.
23. The method of claim 20, further comprising:
providing the generated bit stream signal to a parallel to serial converter.
24. A method of converting a parallel input to a serial output, the method comprising:
receiving a parallel data input;
generating a bit stream signal having a plurality of bit transitions, wherein the plurality of bit transitions have a frequency in a first ratio with respect to the frequency of a first clock signal wherein a first set of the plurality of bit transitions have timing that is derived based on selected edges of a second clock signal; and
converting the parallel data input to a serial output based on the generated bit stream signal.
25. The method of claim 23, further comprising:
converting a sample rate of the parallel data input based on a sample rate control signal.
26. The method of claim 23, wherein generating the bit stream signal includes calculating a second ratio between a rate of the second clock signal and a rate of the first clock signal and generating the bit stream signal based on a relationship between the second ratio and a sample rate control input.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A collision determining apparatus for a vehicle comprising:
a vibration detection device that detects a high-frequency vibration of an audio band generated in a vehicle and a low-frequency vibration of the audio band which is lower than the high-frequency vibration; and
a collision determining device that determines whether or not a collision requiring an activation of an occupant protection apparatus of the vehicle has occurred based on the detection result of the high-frequency vibration and the low-frequency vibration.
2. The collision determining apparatus for a vehicle according to claim 1,
wherein the vibration detection device includes:
a first vibration sensor that detects a frequency band from 5 kHz to 20 kHz as the high-frequency vibration of the audio band; and
a second vibration sensor that detects a frequency band from 0 Hz to 500 Hz as the low-frequency vibration of the audio band which is lower than the high-frequency vibration.
3. The collision determining apparatus for a vehicle according to claim 2,
wherein both of the first vibration sensor and the second vibration sensor are built in a sensor cell.
4. A collision determining apparatus for a vehicle comprising:
a vibration detection device that detects a broad-band vibration generated in a vehicle;
a first extraction device that extracts a high-frequency vibration of an audio band from the broad-band vibration detected by the vibration detection device;
a second extraction device that extracts a low-frequency vibration of the audio band which is lower than the high-frequency vibration from the broad-band vibration detected by the vibration detection device; and
a collision determining device that determines whether or not a collision requiring an activation of an occupant protection apparatus of the vehicle has occurred based on the detection result of the high-frequency vibration and the low-frequency vibration.
5. The collision determining apparatus for a vehicle according to claim 4,
wherein the first extraction device extracts the frequency band from 5 kHz to 20 kHz from the broad-band vibration, as the high-frequency vibration of the audio band and the second extraction device extracts the frequency band from 0 Hz to 500 Hz from the broad-band vibration as the low-frequency vibration of the audio band which is lower than the high-frequency vibration.
6. The collision determining apparatus for a vehicle according to claim 1,
wherein the collision determining device includes:
a first calculation device that calculates a first calculation value based on the detection result of the high-frequency vibration;
a second calculation device that calculates a second calculation value based on the detection result of the low-frequency vibration; and
a map determining device that determines that a collision requiring the activation of the occupant protection apparatus has occurred, when, in a two-dimension map where a first axis is the first calculation value and a second axis is the second calculation value, the first calculation value and the second calculation value calculated by the first calculation device and the second calculation device exceed a two-dimension collision determining threshold value set in two-dimensions.
7. The collision determining apparatus for a vehicle according to claim 1,
wherein the collision determining device includes:
a first calculation device that calculates a first calculation value based on the detection result of the high-frequency vibration;
a second calculation device that calculates a second calculation value based on the detection result of the low-frequency vibration; and
a threshold value determining device that determines that a collision requiring the activation of the occupant protection apparatus has occurred when the first calculation value exceeds a first collision determining threshold value and the second calculation value exceeds a second collision determining threshold value.
8. The collision determining apparatus for a vehicle according to claim 1 further comprising:
a safing determining device that performs a safing determining based on the detection result of the low-frequency vibration; and
a final determining device that finally determines whether or not a collision requiring the activation of the occupant protection apparatus has occurred based on the collision determining result of the collision determining device and the safing determining result of the safing determining device.
9. The collision determining apparatus for a vehicle according to claim 4,
wherein the collision determining device includes:
a first calculation device that calculates a first calculation value based on the detection result of the high-frequency vibration;
a second calculation device that calculates a second calculation value based on the detection result of the low-frequency vibration; and
a map determining device that determines that a collision requiring the activation of the occupant protection apparatus has occurred, when, in a two-dimension map where a first axis is the first calculation value and a second axis is the second calculation value, the first calculation value and the second calculation value calculated by the first calculation device and the second calculation device exceed a two-dimension collision determining threshold value set in two-dimensions.
10. The collision determining apparatus for a vehicle according to claim 4,
wherein the collision determining device includes:
a first calculation device that calculates a first calculation value based on the detection result of the high-frequency vibration;
a second calculation device that calculates a second calculation value based on the detection result of the low-frequency vibration; and
a threshold value determining device that determines that a collision requiring the activation of the occupant protection apparatus has occurred when the first calculation value exceeds a first collision determining threshold value and the second calculation value exceeds a second collision determining threshold value.
11. The collision determining apparatus for a vehicle according to claim 4 further comprising:
a safing determining device that performs a safing determining based on the detection result of the low-frequency vibration; and
a final determining device that finally determines whether or not a collision requiring the activation of the occupant protection apparatus has occurred based on the collision determining result of the collision determining device and the safing determining result of the safing determining device.