1. A method for identifying a jitter component of a digital signal with a repetitive bit sequence of a plurality of bits, comprising:
determining a distribution function of a transition within the repetitive bit sequence, by:
a) setting a sample point at a first sampling position relative to the first transition,
b) assigning a set of digital values to comparison results of the digital signal with a threshold for a plurality of repetitions of the repetitive bit sequence,
c) determining a distribution value on the base of the sum of assigned digital values,
d) shifting the sample point by a time increment,
e) iteratively repeating steps b) to d) until the sample point has reached a second sampling position relative to the transition, and
f) determining from the distribution values a distribution function over the sample points, and
determining for each distribution function an intersection point,
identifying a latest time value and an earliest time value of all rising transitions, and determining a first absolute time difference therefrom,
identifying a latest time value and an earliest time value of all falling transitions, and determining a second absolute time difference therefrom, and
determining an inter symbol interference value by determining the maximum value out of the first absolute time difference and the second absolute time difference.
2. The method of claim 1, further comprising
identifying a first mean value of the time deviation values of all rising transitions,
identifying a second mean value of the time deviation values of all falling transitions, and
determining a duty cycle distortion value by determining an absolute difference of the first mean value and the second mean value.
3. The method of claim 1, wherein shifting the sample point by a time increment is performed by a variable delay element the delay of which is incremented stepwise.
4. The method of claim 1, wherein shifting the sample point is performed by sampling the signal with a sampling rate which has a predetermined fraction of the bit rate.
5. The method of claim 1, wherein each sample is stored in a capture memory and the determination of the distribution functions are performed after taking all samples.
6. The method of claim 1, wherein
the assigned values of a transition are compared with a known bit value of the digital signal, and
a bit error ratio \u2014BER\u2014 of a number of bit differences in relation to a number of repetitions is determined, in order to obtain the distribution value.
7. The method of claim 1, wherein each sample point is set by automatically aligning it with a transition of the signal.
8. A software program or product, stored on a computer readable medium, for executing the method of claim 1, when run on a data processing system.
9. The method of claim 1, further comprising:
determining for each distribution function an intersection point with a defined threshold, at 50% of a bit amplitude,
determining for each intersection point a time deviation value with respect to a corresponding ideal transition time point, wherein the ideal transition time points are equally spaced with a time distance according to the bit rate, and
identifying the jitter component as a function of the time deviation values.
10. The method of claim 9, further comprising
identifying a latest time value and an earliest time value out of the determined time deviation values, and
determining a data dependent jitter by taking the absolute difference between the latest time value and the earliest time value.
11. A method for identifying a jitter component of a digital signal with a repetitive bit sequence of a plurality of bits, comprising:
determining a distribution function a transition within the repetitive bit sequence, by:
a) setting a sample point at a first sampling position relative to the first transition,
b) assigning a set of digital values to comparison results of the digital signal with a threshold for a plurality of repetitions of the repetitive bit sequence,
c) determining a distribution value on the base of the sum of assigned digital values,
d) shifting the sample point by a time increment,
e) iteratively repeating steps b) to d) until the sample point has reached a second sampling position relative to the transition, and
f) determining from the distribution values a distribution function over the sample points, and
determining for each distribution function an intersection point,
wherein the intersection points are chosen to relate to a BER of 50%, so that they relate to most likely transition points.
12. A method for identifying a jitter component of a digital signal with a repetitive bit sequence of a plurality of bits, comprising:
setting a plurality of sample points at a plurality of sampling positions at ideal transition points,
assigning each of a set of digital values to comparison results of the digital signal with a threshold for a plurality of repetitions of the bit sequence,
determining for each sample point a one shot value on the base of the sum of each of the assigned digital values, fitting a predetermined distribution function of one transition each to the one-shot-values,
determining time deviations values by determining the time differences between each one-shot-value and a 50% BER value, and
identifying the jitter property as a function of the time deviation values.
13. A method for identifying a jitter component of a digital signal with a repetitive bit sequence of a plurality of bits, comprising:
determining a distribution function of a transition within the repetitive bit sequence, by:
a) setting a sample point at a first sampling position relative to the first transition,
b) assigning a set of digital values to comparison results of the digital signal with a threshold for a plurality of repetitions of the repetitive bit sequence,
c) determining a distribution value on the base of the sum of assigned digital values,
d) shifting the sample point by a time increment,
e) iteratively repeating steps b) to d) until the sample point has reached a second sampling position relative to the transition, and
f) determining from the distribution values a distribution function over the sample points,
wherein a determined random jitter is added to one of the: digital signal or a sampling clock, so that the distribution function is stretched with respect to a time axis.
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 method of locating a printhead on a printer, the method comprising the steps of:
providing a printhead comprising at least one integrated circuit having a plurality of ejection nozzles;
mounting the printhead to the printer by bringing each of a slot defined with respect to the x-coordinate of the printhead into cooperation with a mesa feature of the printer, an angled surface defined with respect to the x- and y-coordinates of the printhead into cooperation with a protrusion across the slot of the printer, and a flat surface defined with respect to the z-coordinate of the printhead into cooperation with protrusion located within the slot of the printer; and
determining from the cooperation the location of the nozzles with respect to the x-, y- and z-coordinates.
2. A method according to claim 1, wherein the printhead has an elongate ink distribution support mounting the, or each, integrated circuit so that the, or each, integrated circuit extends longitudinally along the elongate support.
3. A method according to claim 2, wherein the, or each, integrated circuit is mounted along the elongate support so that the nozzles create a printing zone which extends across a pagewidth.
4. A method according to claim 2, wherein the elongate support is formed as a molding, and the slot, angled surface and flat surface are molded as part of the support molding.
5. A method according to claim 2, wherein the flat surface is provided at either longitudinal end of the elongate support.
6. A method according to claim 2, wherein the slot is defined in the ink distribution support.
7. A method according to claim 2, wherein the flat surface is defined at a plurality of corners of the ink distribution support.
8. A method according to claim 3, wherein the slot, angled surface and flat surface are arranged beyond the longitudinal extent of the printing zone.
9. A method according to claim 4, wherein the molding is formed from liquid crystal polymer.
10. A method according to claim 9, wherein the integrated circuit is formed from a silicon wafer.
11. A method according to claim 10, wherein the liquid crystal polymer of the ink distribution support has thermal expansion characteristics similar to those of the silicon of the integrated circuit.