BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to frequency compensation, and more particularly, to a frequency compensation method which can compensate a frequency in a flexible manner, and a related apparatus.
2. Description of the Prior Art
In modern television (TV) systems which utilize analog modulation techniques, the television system will perform an auto detection operation to derive a standard audio frequency in each band, and then a receiver of the television system sets carrier frequency and analyzes TV signals according to the standard audio frequency. However, the TV signal may have a frequency offset, resulting in an auto detection failure or an erroneous judgment of the standard audio frequency. Additionally, the receiver usually utilizes an auto frequency compensation mechanism to compensate the audio frequency dynamically. If the frequency offset increases, the frequency compensation time of the TV signal will be longer, causing discomfort to the user's hearing. Therefore, there is a need to provide a rapid frequency compensation method that can be operated in the receiver of the TV system.
SUMMARY OF THE INVENTION
It is therefore one of the objectives of the present invention to provide a frequency compensation method which can compensate a frequency in a flexible manner, and a related apparatus, to solve the above mentioned problems.
According to an embodiment of the present invention, an exemplary method for frequency compensation is disclosed. The exemplary method includes the following steps: detecting and checking if a desired frequency falls within a first detectable frequency range delimited by an initial frequency and a first specific frequency; and when the desired frequency exceeds the first detectable frequency range, utilizing a first frequency compensation step with a step size greater than a size of the first detectable frequency range for shifting the initial frequency to a first adjusted frequency beyond the first specific frequency in a first direction.
According to another embodiment of the present invention, an exemplary frequency compensation apparatus is provided. The exemplary frequency compensation apparatus includes a detecting unit and a compensation unit. The detecting unit is used for detecting and checking if a desired frequency falls within a first detectable frequency range delimited by an initial frequency and a first specific frequency to generate a first detecting result. The compensation unit is coupled to the detecting unit, and implemented for compensating the initial frequency to a first adjusted frequency according to the first detecting result generated by the detecting unit. When the first detecting result indicates that the desired frequency exceeds the first detectable frequency range, the compensation unit utilizes a first frequency compensation step with a step size greater than a size of the first detectable frequency range for shifting the initial frequency to the first adjusted frequency beyond the first specific frequency in a first direction.
According to another embodiment of the present invention, an exemplary method for frequency compensation is disclosed. The exemplary method includes the following steps: detecting and checking if a desired frequency falls within a detectable frequency range, wherein an initial frequency is located at a center of the detectable frequency range; and when the desired frequency exceeds the detectable frequency range, utilizing a frequency compensation step with a step size greater than a half size of the detectable frequency range for updating the initial frequency by shifting the initial frequency to an adjusted frequency.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flowchart illustrating a method for frequency compensation according to an exemplary embodiment of the present invention.
FIG. 2 is a diagram illustrating a frequency compensation apparatus according to an exemplary embodiment of the present invention.
FIG. 3 is a flowchart illustrating a method for frequency compensation according to an exemplary embodiment of the present invention.
FIG. 4 is a sequence diagram illustrating a frequency compensation procedure according to a first exemplary embodiment of the present invention.
FIG. 5 is a sequence diagram illustrating a frequency compensation procedure according to a second exemplary embodiment of the present invention.
FIG. 6 is a sequence diagram illustrating a frequency compensation procedure according to a third exemplary embodiment of the present invention.
FIG. 7 is a sequence diagram illustrating a frequency compensation procedure according to a fourth exemplary embodiment of the present invention.
DETAILED DESCRIPTION
Certain terms are used throughout the following description and claims to refer to particular components. As one skilled in the art will appreciate, hardware manufacturers may refer to a component by different names. This document does not intend to distinguish between components that differ in name but in function. In the following discussion and in the claims, the terms “include”, “including”, “comprise”, and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . ”. The terms “couple” and “coupled” are intended to mean either an indirect or a direct electrical connection. Thus, if a first device couples to a second device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections.
Please refer to FIG. 1. FIG. 1 is a flowchart illustrating a method for frequency compensation according to an exemplary embodiment of the present invention. Please note that, provided the same result is substantially achieved, the steps of the flow shown in FIG. 1 need not be in the exact order shown and need not be contiguous; that is, other steps can be intermediate. The exemplary method for frequency compensation includes the following steps:
Step 102: set an initial frequency Fini.
Step 104: detect and check if a desired frequency Fde falls within a detectable frequency range R, wherein the initial frequency Fini is located at a center of the detectable frequency range R. If yes, go to step 112; otherwise, go to step 106.
Step 106: detect and check if a current frequency compensation direction D needs to be reversed. If yes, go to step 110; otherwise, go to step 108.
Step 108: utilize a frequency compensation step Sfc with a step size greater than a half size of the detectable frequency range R and equal to a default value Vd for shifting the initial frequency Fini to an adjusted frequency Fadj, and then go to step 104.
Step 110: reduce a current value of the step size of the frequency compensation step Sfc, and then utilize the frequency compensation step Sfc with the step size equal to a reduced value Vr for shifting the initial frequency Fini to the adjusted frequency Fadj, and then go to step 104.
Step 112: shift the initial frequency Fini to the desired frequency Fde directly.
In step 110, the current value of the step size of the frequency compensation step Sfc can be gradually decreased or reduced by half to derive the frequency compensation step Sfc with the step size equal to the reduced value Vr. In addition, for clarity and simplicity illustrating the spirits of the present invention, the following embodiments of the present invention will be described in detail with reference to the accompanying drawings, and the current value of the step size of the frequency compensation step Sfc is reduced by half to derive the frequency compensation step Sfc with the step size equal to the reduced value Vr. It is to be noted, however, that the present invention is not limited thereto.
Please refer to FIG. 2. FIG. 2 is a diagram illustrating a frequency compensation apparatus 200 according to an exemplary embodiment of the present invention. The frequency compensation apparatus 200 includes, but is not limited to, a detecting unit 210, a compensation unit 220 and a setting unit 230. The detecting unit 210 is used for detecting and checking if the desired frequency Fde of an input signal (e.g., a television signal STV) falls within a first detectable frequency range R1 delimited by the initial frequency Fini and a first specific frequency Fs1 to generate a detecting result Dr, wherein a size of the detectable frequency range R mentioned above is twice greater than that of the first detectable frequency range R1. The compensation unit 220 is coupled to the detecting unit 210, and implemented for compensating the initial frequency Fini to the desired frequency Fde according to the detecting result Dr generated by the detecting unit 210. When the detecting result Dr (e.g., a first detecting result Dr1) indicates that the desired frequency Fde exceeds the first detectable frequency range R1, the compensation unit 220 utilizes a first frequency compensation step Sfc1 with a step size greater than the size of the first detectable frequency range R1 (i.e., the frequency compensation step Sfc with the step size greater than the half size of the detectable frequency range R and equal to the default value Vd) for shifting the initial frequency Fini to a first adjusted frequency Fadj1 beyond the first specific frequency Fs1 in a first direction D1; When the detecting result Dr (e.g., the first detecting result Dr1) indicates that the desired frequency Fde falls within the first detectable frequency range R1, the compensation unit 220 shifts the initial frequency Fini to the desired frequency Fde directly.
In this exemplary embodiment, the setting unit 230 is coupled to the detecting unit 210, and implemented for detecting an audio standard frequency Fas of the television signal STV and setting the audio standard frequency Fas as the initial frequency Fini in the first frequency compensation session of the frequency compensation procedure. After shifting the initial frequency Fini to the first adjusted frequency Fadj1 according to the first detecting result Dr1, the detecting unit 210 further detects and checks if the desired frequency Fde falls within a second detectable frequency range R2 delimited by the first adjusted frequency Fadj1 and a second specific frequency Fs2, thereby generating the detecting result Dr (e.g., a second detecting result Dr2), wherein the size of the detectable frequency range R is also twice greater than that of the second detectable frequency range R2. When the detecting result Dr (e.g., the second detecting result Dr2) indicates that the desired frequency Fde exceeds the second detectable frequency range R2, the compensation unit 220 utilizes a second frequency compensation step Sfc2 (i.e., the frequency compensation step Sfc with the step size equal to the reduced value Vr), having a step size greater than a size of the second detectable frequency range R2 and smaller than the step size of the first frequency compensation step Sfc1, for shifting the first adjusted frequency Fadj1 to a second adjusted frequency Fadj2 beyond the second specific frequency Fs2 in a second direction D2 opposite to the first direction D1. When the detecting result Dr (e.g., the second detecting result Dr2) indicates that the desired frequency Fde falls within the second detectable frequency range R2, the compensation unit 220 shifts the first adjusted frequency Fadj1 to the desired frequency Fde directly.
Please refer to FIG. 3. FIG. 3 is a flowchart illustrating a method for frequency compensation according to an exemplary embodiment of the present invention. Please note that, provided the same result is substantially achieved, the steps of the flow shown in FIG. 3 need not be in the exact order shown and need not be contiguous; that is, other steps can be intermediate. The exemplary method for frequency compensation includes the following steps:
Step 302: set an initial frequency Fini.
Step 304: detect and check if the desired frequency Fde falls within a specific detectable frequency range Rs (e.g., the first detectable frequency range R1 or the second detectable frequency range R2) delimited by the initial frequency Fini and a specific frequency Fs (e.g., the first specific frequency Fs1 or the second specific frequency Fs2). If yes, go to step 312; otherwise, go to step 306.
Step 306: detect and check if the frequency compensation direction D (e.g., D1 and D2) has been reversed. If yes, go to step 310; otherwise, go to step 308.
Step 308: utilize the first frequency compensation step Sfc1 with a step size greater than the size of the first detectable frequency range R1 for shifting the initial frequency Fini, and then go to step 304.
Step 310: utilize the second frequency compensation step Sfc2, having the step size smaller than the step size of the first frequency compensation step Sfc1 for shifting the initial frequency Fini, and then go to step 304.
Step 312: shift the initial frequency Fini to the desired frequency Fde directly.
Please note that, for clarity and simplicity, the following embodiments of the present invention will be described in detail with reference to the accompanying drawings. It is to be noted, however, that the present invention is not limited thereto. Please refer to FIG. 4 in conjunction with FIG. 2 and FIG. 3. FIG. 4 is a sequence diagram illustrating a frequency compensation procedure according to a first exemplary embodiment of the present invention. In this embodiment, the first detectable frequency range R1 is equal to the second detectable frequency range R2 and a third detectable frequency range R3, the step size of the first frequency compensation step Sfc1 is four times as great as that of the first detectable frequency range R1, and the step size of the first frequency compensation step Sfc1 is twice that of the second frequency compensation step Sfc2, but these parameters should not be taken as limitations of the present invention. As shown in FIG. 4, the setting unit 230 executes step 302 to set the initial frequency Fini in the first frequency compensation session of the frequency compensation procedure. The detecting unit 210 executes step 304 to detect and check that the desired frequency Fde exceeds the first detectable frequency range R1 delimited by the initial frequency Fini and the first specific frequency Fs1 in a first direction D1. The detecting unit 210 executes step 306 to check that the frequency compensation direction does not reverse. The compensation unit 220 executes step 308 to utilize the first frequency compensation step Sfc1 for shifting the initial frequency Fini to the first adjusted frequency Fadj1. In the following second frequency compensation session of the frequency compensation procedure, the adjusted frequency Fadj1 serves as an initial frequency, and the detecting unit 210 therefore executes step 304 to detect and check that the desired frequency Fde exceeds the second detectable frequency range R2 delimited by the first adjusted frequency Fadj1 and the second specific frequency Fs2 in the second direction D2. The detecting unit 210 executes step 306 to check that the frequency compensation direction is reversed. Thus, the compensation unit 220 executes step 310 to utilize the second frequency compensation step Sfc2 for shifting the first adjusted frequency Fadj1 to the second adjusted frequency Fadj2. In the following third compensation session of the frequency compensation procedure, the second adjusted frequency Fadj2 serves as an initial frequency, and the detecting unit 210 executes step 304 to detect and check that the desired frequency Fde falls within the third detectable frequency range R3 delimited by the second adjusted frequency Fadj2 and the first specific frequency Fs1 in the second direction D2. The compensation unit 220 executes step 312 to shift the second adjusted frequency Fadj2 to the desired frequency Fde directly, thereby accomplishing the frequency compensation procedure.
Please refer to FIG. 5 in conjunction with FIG. 2 and FIG. 3. FIG. 5 is a sequence diagram illustrating a frequency compensation procedure according to a second exemplary embodiment of the present invention. In this embodiment, the first detectable frequency range R1 is equal to the second detectable frequency range R2 and the third detectable frequency range R3, the step size of the first frequency compensation step Sfc1 is four times as great as that of the first detectable frequency range R1, and the step size of the first frequency compensation step Sfc1 is twice that of the second frequency compensation step Sfc2, but these parameters should not be taken as limitations of the present invention. As shown in FIG. 5, the setting unit 230 executes step 302 to set the initial frequency Fini in the first frequency compensation session of the frequency compensation procedure. The detecting unit 210 executes step 304 to detect and check that the desired frequency Fde exceeds the first detectable frequency range R1 delimited by the initial frequency Fini and a first specific frequency Fs1 in a first direction D1. The detecting unit 210 executes step 306 to check that the frequency compensation direction does not reverse. The compensation unit 220 executes step 308 to utilize the first frequency compensation step Sfc1 for shifting the initial frequency Fini to the first adjusted frequency Fadj1. In the following second frequency compensation session of the frequency compensation procedure, the first adjusted frequency Fadj1 serves as an initial frequency, and the detecting unit 210 executes step 304 to detect and check that the desired frequency Fde exceeds the second detectable frequency range R2 delimited by the first adjusted frequency Fadj1 and the second specific frequency Fs2 in the second direction D2. The detecting unit 210 executes step 306 to check that the frequency compensation direction is reversed. Thus, the compensation unit 220 executes step 310 to utilize the second frequency compensation step Sfc2 for shifting the first adjusted frequency Fadj1 to the second adjusted frequency Fadj2. In the following third frequency compensation session of the frequency procedure, the second adjusted frequency Fadj2 serves as an initial frequency, and the detecting unit 210 executes step 304 to detect and check that the desired frequency Fde falls within the third detectable frequency range R3 delimited by the second adjusted frequency Fadj2 and the second specific frequency Fs2 in the first direction D1. The compensation unit 220 executes step 312 to shift the second adjusted frequency Fadj2 to the desired frequency Fde directly, thereby accomplishing the frequency compensation procedure.
Please refer to FIG. 6 in conjunction with FIG. 2 and FIG. 3. FIG. 6 is a sequence diagram illustrating a frequency compensation procedure according to a third exemplary embodiment of the present invention. In this embodiment, the first detectable frequency range R1 is equal to the second detectable frequency range R2, and the step size of the first frequency compensation step Sfc1 is four times as great as that of the first detectable frequency range R1, but these parameters should not be taken as limitations of the present invention. As shown in FIG. 6, the setting unit 230 executes step 302 to set the initial frequency Fini in the first frequency compensation session of the frequency compensation procedure. The detecting unit 210 executes step 304 to detect and check that the desired frequency Fde exceeds the first detectable frequency range R1 delimited by the initial frequency Fini and a first specific frequency Fs1 in a first direction D1. The detecting unit 210 executes step 306 to check that the frequency compensation direction does not reverse. The compensation unit 220 executes step 308 to utilize the first frequency compensation step Sfc1 for shifting the initial frequency Fini to the first adjusted frequency Fadj1. In the following second frequency compensation session of the frequency compensation procedure, the first adjusted frequency Fadj1 serves as an initial frequency, and the detecting unit 210 executes step 304 to detect and check that the desired frequency Fde falls within the second detectable frequency range R2 delimited by the first adjusted frequency Fadj1 and the second specific frequency Fs2 in the second direction D2. The compensation unit 220 executes step 312 to shift the first adjusted frequency Fadj1 to the desired frequency Fde directly, thereby accomplishing the frequency compensation procedure.
Please refer to FIG. 7 in conjunction with FIG. 2 and FIG. 3. FIG. 7 is a sequence diagram illustrating a frequency compensation procedure according to a fourth exemplary embodiment of the present invention. In this embodiment, the first detectable frequency range R1 is equal to the second detectable frequency range R2, and the step size of the first frequency compensation step Sfc1 is four times as great as that of the first detectable frequency range R1, but these parameters should not be taken as limitations of the present invention. As shown in FIG. 7, the setting unit 230 executes step 302 to set the initial frequency Fini in the first frequency compensation session of the frequency compensation procedure. The detecting unit 210 executes step 304 to detect and check that the desired frequency Fde exceeds the first detectable frequency range R1 delimited by the initial frequency Fini and a first specific frequency Fs1 in a first direction D1. The detecting unit 210 executes step 306 to check that the frequency compensation direction does not reverse. The compensation unit 220 executes step 308 to utilize the first frequency compensation step Sfc1 for shifting the initial frequency Fini to the first adjusted frequency Fadj1. In the following second frequency compensation session of the frequency compensation procedure, the first adjusted frequency Fadj1 serves as an initial frequency, and the detecting unit 210 executes step 304 to detect and check that the desired frequency Fde falls within the second detectable frequency range R2 delimited by the first adjusted frequency Fadj1 and the second specific frequency Fs2 in the first direction D1. The compensation unit 220 executes step 312 to shift the first adjusted frequency Fadj1 to the desired frequency Fde directly, thereby accomplishing the frequency compensation procedure.
As can be seen from FIG. 4 through FIG. 7, the exemplary frequency compensation apparatus 200 of the present invention is allowed to utilize a frequency compensation step with a step size greater than that of the detectable frequency range, such as R1, R2 or R3, to compensate the initial frequency. However, in the prior art design, the conventional frequency compensation apparatus can only compensate the initial frequency with a step size smaller than or equal to the detectable frequency range. Therefore, if the initial frequency is located far from the desired frequency, the frequency compensation apparatus 200 can compensate the initial frequency with a flexible frequency compensation step, decreasing the compensation time greatly.
The abovementioned embodiments are presented merely for describing features of the present invention, and in no way should be considered to be limitations of the scope of the present invention. In other words, the exemplary frequency compensation procedures shown in FIGS. 4-7 are for illustrative purposes only.
In summary, exemplary embodiments of the present invention provide a frequency compensation method which can compensate a frequency in a flexible manner, and a related apparatus. By utilizing a flexible frequency compensation step with a step size greater than the size of the detectable frequency range, the exemplary frequency compensation apparatus of the present invention can compensate the initial frequency quickly when the initial frequency is located far from the desired frequency, leading to improved frequency compensation performance.
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention.
Patent Application
20110187937
