Abstract:
A set top box includes a central processing unit, which generates the first accompaniment signals according to a music file, when voice signals is received, they will be converted into stereo voice signals, and the stereo voice signals is converted into digital voice signals, and the set top box adjusts the first accompaniment signals to output second accompaniment signals, mixes the second accompaniment signals and the digital voice signals to output mixing audio signals to the central processing unit, at last converts the mixing audio signals into digital stereo signals, and outputs the digital stereo signals.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    Embodiments of the present disclosure relate to devices that process audio signals, and more particularly to a set top box that processes audio signals. 
         [0003]    2. Description of Related Art 
         [0004]    With the advent of technology, digitized audio media has gained popularity. A set top box (STB) may be used to provide audio digitization, such as a karaoke function. 
         [0005]    Presently, due to digital-to-analog (D/A) and analog-to-digital (A/D) conversions, the set top box usually may output a delayed audio signals when the set top box is providing the karaoke function. As a result, the video and audio output by the set top box are usually difficult to synchronize. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The details of the disclosure, both as to its structure and operation, can best be understood by referring to the accompanying drawings, in which like reference numbers and designations refer to like elements. 
           [0007]      FIG. 1  is a diagram of one embodiment of a set top box of the present disclosure; and 
           [0008]      FIG. 2  is a diagram of another embodiment of a set top box of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0009]      FIG. 1  is a diagram of one embodiment of a set top box  10  of the present disclosure. In one embodiment, the set top box  10  includes an audio analyzing module  112 , an A/D converting module  114 , a central processing unit  116 , an accompaniment processing module  118 , and a digital audio mixer  124 . In one embodiment, the set top box  10  is connected to a microphone  30  to process voice signals input by the microphone  30 , and output digital stereo signals. 
         [0010]    In one embodiment, the audio analyzing module  112  is connected to the microphone  30 , and is operable to receive monaural voice signals from the microphone  30 , and convert the voice signals into stereo voice signals. 
         [0011]    The A/D converting module  114 , connected to the audio analyzing module  112 , is operable to receive the stereo voice signals from the audio analyzing module  112 , and convert the stereo voice signals into digital voice signals. 
         [0012]    The central processing unit  116  is operable to output signals corresponding to music files stored in the set top box  10 , to the accompaniment processing module  118 . These signals are known as first accompaniment signals. 
         [0013]    The accompaniment processing module  118 , connected to the central processing unit  116 , is operable to adjust attributes of the first accompaniment signals to output second accompaniment signals. The attributes comprise volume, tone, switching mode and mode of accompaniment mode of the first accompaniment signals. In one embodiment, the accompaniment processing module  118  connects to the central processing unit  116  via a selective one of an inter-IC sound (I 2 S) Bus, a normal bus, and a pulse code modulation (PCM) bus. 
         [0014]    The digital audio mixer  120  is operable to mix the second accompaniment signals from the accompaniment processing module  118  and the digital voice signals from the A/D converting module  114  to output mixing audio signals (i.e., signals that have been mixed) to the central processing unit  116 . In one embodiment, the input of the digital audio mixer  120  is connected to the A/D converting module  114  and the accompaniment processing module  118 , and the output of the digital audio mixer  120  is connected to the central processing unit  116 . 
         [0015]    In one embodiment, the mixing audio signals are transmitted to the central processing unit  116  via one of the I 2 S Bus, the normal bus, and the PCM bus. In other words, the digital audio mixer  120  is connected to the central processing unit  116  via one of the I 2 S Bus, the normal bus, and the PCM bus. 
         [0016]    In one embodiment, the central processing unit  116  is further operable to convert the mixing audio signals into digital stereo signals, and output the digital stereo signals. In one embodiment, the central processing unit  116  is further operable to code and decode video signals. In this disclosure, the voice signals are converted into the digital stereo signals via one A/D conversion, and thereby the delay time of the digital stereo signals is reduced. 
         [0017]    Meanwhile, the central processing unit  116  is further operable to output video signals. Due to the reduced delay time of the digital stereo signals, the synchronization between the un-synchronization between the video signals and the digital stereo signals is improved. 
         [0018]      FIG. 2  is a diagram of another embodiment of a set top  20  box of the present disclosure. In one embodiment, the set top box  20  includes an audio processor  210 , an audio mixer  220 , and a central processing unit  230 . The audio processor  210  includes an audio analyzing module  212 , an accompaniment processing module  214 , a voice effect processing module  216 , and a mixer  218 . The audio mixer  220  includes an A/D converting module  222  and a digital audio mixer  224 . 
         [0019]    In one embodiment, the central processing unit  230 , the accompaniment processing module  214 , and the A/D converting module  222  have respectively the same function as the central processing unit  116 , the accompaniment processing module  118 , and the A/D converting module  114  in  FIG. 1 , and therefore the detailed descriptions are omitted. 
         [0020]    In one embodiment, the audio processor  210  is connected to the central processing unit  230 , and is operable to process first accompaniment signals and the voice signals. In one embodiment, the audio processor  210  may be an integrated chip, such as one of a series of YSS915 chips. In one embodiment, the audio processor  210  can be connected to the central processing unit  230  via one of the I 2 S Bus, the normal bus, and the PCM bus. 
         [0021]    In one embodiment, the audio analyzing module  212 , connected to the microphone  30 , is operable to receive voice signals input by the microphone  30 , and convert the monaural signals into stereo voice signals. 
         [0022]    In one embodiment, the audio analyzing module  212  is further operable to generate audio parameters according to the voice signals. In one embodiment, the audio parameters include volume and tone of the voice signals. 
         [0023]    In one embodiment, the voice effect processing module  216 , connected to the audio analyzing module  212  is operable to generate voice effect signals according to the audio parameters. In one embodiment, the voice effect signals include reverberation, re-echo, and inflection. In one embodiment, the voice effect signals are digital signals. 
         [0024]    The mixer  218  is operable to mix the second accompaniment signals from the accompaniment processing module  214  and the voice effect signals from the voice effect processing module  216  to output third accompaniment signals to the digital audio mixer  224 . In one embodiment, an input of the mixer  218  is connected to the voice effect processing module  216  and the accompaniment processing module  214 , and an output of the mixer  218  is connected to the digital audio mixer  224 . 
         [0025]    The audio mixer  220  is operable to mix the third accompaniment signals and the digital voice signals to output mixing audio signals to the central processing unit  230 . 
         [0026]    In one embodiment, an input of the audio mixer  220  is connected to the audio processor  210 , and an output of the audio mixer  220  is connected to the central processing unit  230 . 
         [0027]    In one embodiment, the audio mixer  220  connects to the audio processor  210  and the central processing unit  230  via one of the I 2 S Bus, the normal bus, and the PCM bus. In one embodiment, the stereo voice signals can be converted into the digital voice signals via the audio mixer  220 . The audio mixer  220  may be an integrated chip, such as digital mixer embedded A/D converter. 
         [0028]    In one embodiment, the digital audio mixer  224  connected to the mixer  218  is operable to mix the third accompaniment signals from the mixer  218  and the digital voice signals from the A/D converting module  222  to output mixing audio signals to the central processing unit  230 . In one embodiment, the input of the digital audio mixer  224  is connected to the mixer  218  and the A/D converting module  222 . 
         [0029]    In one embodiment, the central processing unit  230  is further operable to code and decode video signals. In this disclosure, the voice signals are converted into the digital stereo signals via one A/D conversion, and thereby the delay time of the digital stereo signals is reduced. 
         [0030]    Meanwhile, the central processing unit  230  is further operable to output the video signals. Due to the reduced delay time of the digital stereo signals, the synchronization between the video signals and the digital stereo signals is improved. 
         [0031]    In this disclosure, the set top box  10  can reduce the frequency of A/D conversion through the audio analyzing module  112 , the A/D converting module  114 , the central processing unit  116 , the accompaniment processing module  118 , and the digital audio mixer  120 . The set top box  10  can reduce the classes of processing, reduce the audio processing delay time, and improve the quality of the voice signals, thereby reducing time during which audio signals and video signals are not synchronized, and provide video and audio synchronization. 
         [0032]    Although the features and elements of the present disclosure are described in various inventive embodiments in particular combinations, each feature or element can be configured alone or in various within the principles of the present disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.