1. A paper roll remaining amount detecting device, the device comprising:
a paper roll receiving unit including a rest portion configured to support, depending on a printer mounting posture, an outer circumferential surface of a paper roll formed of a cylindrical core and first and second recesses formed in the rest portion to receive the paper roll dropping by the weight of the paper roll when the paper roll is consumed to have a predetermined winding diameter;
an attachment frame pivotably supported on an outer surface of a sidewall of the paper roll receiving unit through a pivot shaft to pivot about the pivot shaft by the weight of the attachment frame, the sidewall of the paper roll receiving unit having an arc-shaped hole portion extending along a pivot movement trajectory of a pivoting end portion of the attachment frame;
an arm pivotably supported on the attachment frame, the arm including a projection formed in a pivoting end portion thereof and inserted into the arc-shaped hole portion of the sidewall of the paper roll receiving unit, the arm configured to operate such that, when the paper roll becomes equal to or smaller than a predetermined size by the consumption of the paper roll, the projection of the arm is moved toward the cylindrical core of the paper roll; and
a detecting unit configured to detect, based on the operation of the arm, whether the paper roll is equal to or smaller than the predetermined size.
2. The device of claim 1, further comprising:
a biasing member configured to elastically bias the arm to pivot toward an end surface of the paper roll.
3. The device of claim 2, wherein the detecting unit comprises a sensor configured to be turned on and off as the projection of the arm is moved toward and away from the end surface of the paper roll.
4. A printer, comprising:
a printer body including an attachment portion configured to be selectively attached to one of a vertical surface and a horizontal surface depending on a mounting posture of the printer body;
a printing unit provided within the printer body;
a paper roll receiving unit including a rest portion configured to support, depending on the mounting posture of the printer body, an outer circumferential surface of a paper roll formed of a cylindrical core and first and second recesses formed in the rest portion to receive the paper roll dropping by the weight of the paper roll when the paper roll is consumed to have a predetermined winding diameter;
an attachment frame pivotably supported on an outer surface of a sidewall of the paper roll receiving unit through a pivot shaft to pivot about the pivot shaft by the weight of the attachment frame, the sidewall of the paper roll receiving unit having an arc-shaped hole portion extending along a pivot movement trajectory of a pivoting end portion of the attachment frame;
an arm pivotably supported on the attachment frame, the arm including a projection formed in a pivoting end portion thereof and inserted into the arc-shaped hole portion of the sidewall of the paper roll receiving unit, the arm configured to operate such that, when the paper roll becomes equal to or smaller than a predetermined size by the consumption of the paper roll, the projection of the arm is moved toward the cylindrical core of the paper roll; and
a detecting unit configured to detect, based on the operation of the arm, whether the remaining amount of paper in the paper roll is equal to or smaller than the predetermined size.
5. The printer of claim 4, further comprising:
a biasing member configured to elastically bias the arm to pivot toward an end surface of the paper roll.
6. The printer of claim 5, wherein the detecting unit comprises a sensor configured to be turned on and off as the projection of the arm is moved toward and away from the end surface of the paper roll.
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 scaling path delay values in a communication system in which estimates of received symbols corresponding to the path delays are combined, comprising the steps of:
getting a plurality of path delay values, including getting a set of temporal statistics of the path delay values, the set of temporal statistics including a correlation matrix, a normalized correlation matrix, and a mean energy vector;
identifying the path delay values as either peak values or neighbor values;
organizing the peak values and neighbor values into groups, wherein each group comprises at least one peak value; and
for each group, determining a set of weight values w1 wherein the weight values in a set correspond to respective path delays and are based on at least the set of weight values w determined for the respective group and the set of temporal statistics; and
determining the set of weight values w based on
w=(R+\u03b2I)\u22121(|\u03a9|M*+\u03b21).
in which R is the correlation matrix, M is the mean energy vector, \u03b2 is a selectable parameter, and \u03a9 depends on the normalized correlation matrix and on the mean energy vector and is related to uncorrelated energy or signal-to-interference ratio of a group.
2. The method of claim 1, wherein the weight values are determined by at least the steps of:
checking the groups for duplicated path delay values and
selecting a weight value from the weight values determined for the duplicated path delay values as either one of the weight values for the duplicated path delay values or a combination of the weight values for the duplicated path delay values.
3. The method of claim 1, wherein a set of weight values is determined based on signal correlations.
4. The method of claim 3, wherein in the set of weight values, the weight value for a peak value is a constant and the weight values for neighbor values are the constant less signal correlations.
5. The method of claim 1, wherein a set of weight values is determined as selected constants.
6. A receiver for signals transmitted in a digital communication system, the signals including transmitted symbols, comprising:
a delay selector that determines sets of path delays for received signal echoes;
a propagation channel estimator that determines estimates of an impulse response of a channel through which the transmitted signals have propagated;
a demodulator that determines estimates of the transmitted symbols;
a propagation channel weights computer that determines weight values for path delays determined by the delay selector based on relative correlations of the path delays by identifying the path delays as either peaks or neighbors, organizing the peaks and neighbors into groups, wherein each group comprises at least one peak, and determining a set of weight values w for each group, wherein each weight value in a set corresponds to a respective path delay and is based on at least the set of weight values w determined for the respective group and a set of temporal statistics of the path delays, the set of temporal statistics including a correlation matrix, a normalized correlation matrix, and a mean energy vector;
a combiner that combines the estimates of the impulse response, the estimates of the transmitted symbols, and the weight values, wherein the weight values scale the estimates for the combiner;
wherein, the set of weight values w is determined based on
w=(R+\u03b2I)\u22121(|\u03a9|M*+\u03b21).
in which R is the correlation matrix, M is the mean energy vector, \u03b2 is a selectable parameter, and \u03a9 depends on the normalized correlation matrix and on the mean energy vector and is related to uncorrelated energy or signal-to-interference ratio of a group.
7. The receiver of claim 6, wherein the propagation channel weights computer determines weight values for path delays by checking the groups for duplicated path delays and selecting a weight value from the weight values determined for the duplicated path delays as either one of the weight values for the duplicated path delays or a combination of the weight values for the duplicated path delays.
8. The receiver of claim 6, wherein the propagation channel weights computer determines weight values based on received signal correlations.
9. The receiver of claim 8, wherein in a set of weight values, the weight value for a peak value is a constant and the weight values for neighbor values are the constant less received signal correlations.
10. The receiver of claim 6, wherein the propagation channel weights computer determines weight values as selected constants.
11. A computer-readable medium storing a computer program for scaling path delay values in a communication system in which estimates of received symbols corresponding to the path delays are combined, wherein the computer program performs the steps of:
getting a plurality of path delay values, including getting a set of temporal statistics of the path delay values, the set of temporal statistics including a correlation matrix, a normalized correlation matrix, and a mean energy vector;
identifying the path delay values as either peak values or neighbor values;
organizing the peak values and neighbor values into groups, wherein each group comprises at least one peak value; and
for each group, determining a set of weight values w, wherein each weight value in a set corresponds to a respective path delay and is based on at least the set of weight values w determined for the respective group and the set of temporal statistics determining the set of weight values w based on
w=(R+\u03b2I)\u22121(|\u03a9|M*+1).
in which R is the correlation matrix, M is the mean energy vector, \u03b2 is a selectable parameter, and \u03a9 depends on the normalized correlation matrix and on the mean energy vector and is related to uncorrelated energy or signal-to-interference ratio of a group.
12. The computer-readable medium of claim 11, wherein the computer program determines weight values by at least the steps of:
checking the groups for duplicated path delay values and selecting a weight value from the weight values determined for the duplicated path delay values as either one of the weight values for the duplicated path delay values or a combination of the weight values for the duplicated path delay values.
13. The computer-readable medium of claim 12, wherein the computer program performs the step of getting a plurality of path delay values by at least getting a set of temporal statistics of the path delay values, and a set of weight values is determined based on the set of statistics.
14. The computer-readable medium of claim 12, wherein a set of weight values is determined either based on signal correlations or as selected constants.