1. A method of simulating a circuit comprising:
simulating an analog component of a circuit over a first time portion with a first envelope simulation;
in response to the envelope simulation accuracy falling below a predetermined level of accuracy in comparison with a transient simulation, adaptively switching from simulating the analog component with the first envelope simulation to simulating the analog component with a transient simulation over a second time portion differing from the first time portion; and
adaptively switching from simulating the analog component with the transient simulation to simulating the analog component with a second envelope simulation over a third time portion differing from the first and second time portions.
2. The method of simulating of claim 1, wherein
the adaptive switching from the first envelope simulation to the transient simulation is in response to the second time portion including a digital transition region where one or more digital events can occur.
3. The method of simulating of claim 1, further comprising
checking the smoothness of input signals to detect sharp changes;
and
wherein the adaptive switching from the first envelope simulation to the transient simulation is in response to a detection of a sharp change in one or more input signals.
4. The method of simulating of claim 1, wherein
the adaptive switching from the transient simulation to the second envelope simulation is in response to the third time portion lacking a digital transition region where a digital event may occur and the accuracy of the simulation of the analog component during the third time portion permits a predetermined level of accuracy that the second envelope simulation can achieve in comparison with a transient simulation.
5. The method of simulating of claim 1, wherein
the analog component is a radio-frequency (RF) circuit.
6. A simulation system to simulate a design of a mixed signal integrated circuit, the simulation system comprising:
a processor to execute instructions; and
instructions stored in a storage device that when executed by the processor provide
a digital solver to perform digital simulations of one or more digital portions of the mixed signal integrated circuit;
an analog solver to perform analog simulations of one or more analog portions of the mixed signal integrated circuit;
an envelope simulation engine in communication with the analog solver, the envelope simulation engine to perform envelope simulations of the one or more analog portions of the mixed signal integrated circuit for at least a fist time portion;
a transient simulation engine in communication with the analog solver, the transient simulation engine to perform transient simulations of the one or more analog portions of the mixed signal integrated circuit for at least a second time portion differing from the at least first time portion;
the analog solver includes an adaptive switch in communication with the envelope simulation engine and the transient simulation engine, the adaptive switch to adaptively switch between performing transient simulations and envelope simulations of an analog portion of the mixed signal integrated circuit,
in response to envelope simulation accuracy falling below a predetermined level of accuracy in comparison with a transient simulation, the adaptive switch adaptively switches from envelope simulation of an analog circuit to transient simulation of the analog circuit over at least a third time portion differing from the at least first and second time portions; and
a synchronizer in communication with the digital solver and the analog solver, the synchronizer to periodically synchronize the digital simulations and the analog simulations of the mixed signal integrated circuit respectively performed by the digital solver and the analog solver.
7. The simulation system of claim 6, wherein
the adaptive switch adaptively switches from envelope simulation of an analog circuit to transient simulation of the analog circuit in response to one or more predetermined periods of simulation time where one or more digital events can occur.
8. The simulation system of claim 6, wherein
the adaptive switch adaptively switches from transient simulation of an analog circuit to envelope simulation of the analog circuit in response to the envelope simulation of the analog circuit achieving a predetermined level of accuracy in comparison with the transient simulation.
9. The simulation system of claim 6, wherein
at least one of the envelope simulations performed by the envelope simulation engine of at least one analog portion of the mixed signal integrated circuit is a fast envelope simulation.
10. A computer readable storage medium having computer readable program instructions stored thereon that when executed by a processor performs operations comprising:
simulating an analog component of a circuit over a first time portion with a first envelope simulation;
in response to the envelope simulation accuracy falling below a predetermined level of accuracy in comparison with a transient simulation, adaptively switching from simulating the analog component with the first envelope simulation to simulating the analog component with a transient simulation over a second time portion differing from the first time portion; and
adaptively switching from simulating the analog component with the transient simulation to simulating the analog component with a second envelope simulation over a third time portion differing from the first and second time portions.
11. The computer readable storage medium of claim 10, wherein
the adaptive switching from the first envelope simulation to the transient simulation is in response to the second time portion including a digital transition region where one or more digital events can occur.
12. The computer readable storage medium of claim 10, further comprising instructions that when executed by the machine causes the machine to perform operations comprising:
checking the smoothness of input signals to detect sharp changes;
and
wherein the adaptive switching from the first envelope simulation to the transient simulation is in response to a detection of a sharp change in one or more input signals.
13. The computer readable storage medium of claim 10, wherein
the adaptive switching from the transient simulation to the second envelope simulation is in response to the third time portion lacking a digital transition region where a digital event may occur and the accuracy of the simulation of the analog component during the third time portion permits a predetermined level of accuracy that the second envelope simulation can achieve in comparison with a transient simulation.
14. The computer readable storage medium of claim 10, wherein
the analog component is a radio-frequency (RF) circuit.
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. An electrophotography apparatus comprising:
a template matching circuit configured to determine an image region in an image to be recorded based on original image data from an upper-level controller;
a pulse width modulation circuit configured to generate image data in which the image data is pulse-width modulated based on a result of the determination made in the template matching circuit;
an exposing unit configured to perform exposure based on the image data modulated by the pulse width modulation circuit;
a toner image carrier configured to carry a toner image based on an electrostatic latent image formed by the exposing unit;
a testing patch forming unit configured to form a toner image of a testing patch on the toner image carrier;
an attached toner amount measuring unit configured to measure an amount of toner attached in the testing patch toner image from a front edge to a rear edge thereof;
a testing patch edge detecting unit configured to detect an edge portion of the testing patch toner image where the attached toner amount is greater than in other portions of the testing patch toner image;
a template generating unit configured to generate, based on the edge portion detected by the testing patch edge detecting unit, two kinds of templates having different sizes by determining a number of pixels between a reference pixel position and each of upper, lower, left, and right edges;
an edge pixel region calculating unit configured to perform template matching on the image data to be printed using the templates, wherein a smaller region determined by the larger template is subtracted from a larger region determined by the smaller template to calculate a difference region as an edge pixel region of the image data; and
an exposure amount setting unit configured to set an exposure amount for an electrostatic latent image portion corresponding to the edge pixel region,
wherein the exposure amount for the edge pixel region of the original image data is controlled based on the exposure amount set by the exposure amount setting unit.
2. The electrophotography apparatus according to claim 1, wherein a plurality of testing patches are formed by the testing patch forming unit, wherein the testing patches are exposed with different exposure amounts, and
wherein the exposure amount when the difference in attached toner amount between the front edge portion, the rear edge portion, and an intermediate portion of each of the testing patches is minimum is set in the exposure amount setting unit.
3. The electrophotography apparatus according to claim 1, wherein the testing patch formed on the toner image carrier includes a rectangular patch or a parallelogram patch that is inclined with respect to a direction of movement of the toner image carrier.
4. The electrophotography apparatus according to claim 1, wherein the testing patch edge detecting unit forms a rectangular patch having a front-end edge portion and a rear-end edge portion that are perpendicular to a direction of movement of the toner image carrier, successively measures an attached toner amount in the rectangular patch along the direction of movement of the toner image carrier, and calculates, based on the measured amounts of attached amounts of toner in the rectangular patch, a position of and an attached toner amount in the front-end edge portion and the rear-end edge portion of the rectangular patch where the attached toner amount is increased,
wherein the testing patch edge detecting unit forms a parallelogram patch having a front-end edge portion and a rear-end edge portion that are inclined with respect to the direction of movement of the toner image carrier, successively measures an attached toner amount in the parallelogram patch along the direction of movement of the toner image carrier, and calculates, based on the measured amounts of attached toner in the parallelogram patch, a position of and an attached toner amount in the front-end edge portion and the rear-end edge portion of the parallelogram patch where the attached toner amount is increased,
wherein the testing patch edge detecting unit further calculates a position of and an attached toner amount in a left-side edge portion and a right-side edge portion of the rectangular patch that are parallel to the direction of movement of the toner image carrier where the attached toner amount is increased, based on the positions and attached toner amounts measured for the rectangular patch and the parallelogram patch.
5. The electrophotography apparatus according to claim 4, wherein the template generating unit determines the positions of the front-end edge portion, the rear-end edge portion, the left edge portion, and the right edge portion of the testing patch where the attached toner amount is increased when the exposure amount has a predetermined value, the template generating unit determining a size of each of the two kinds of the templates having different sizes based on the determined positions,
wherein the attached toner amounts at the front-end edge portion, the rear-end edge portion, the left edge portion, and the right edge portion of the testing patch are determined when the exposure amount is varied, wherein an exposure amount that minimizes a difference in attached toner amount between the front-end edge portion and the rear-end edge portion is determined based on the attached toner amounts that are measured when the exposure amount is varied, and the thus determined exposure amount is set in the exposure amount setting unit.
6. The electrophotography apparatus according to claim 1, wherein a distance between an outer contour of the edge pixel region calculated by the edge pixel region calculating unit and a contour of an image portion outside the edge pixel region is greater than a halftone dot interval of a halftone dot image.
7. The electrophotography apparatus according to claim 6, wherein the distance between an outer contour of the edge pixel region calculated by the edge pixel region calculating unit and a contour of an image portion outside the edge pixel region is 4600 inch or greater.