Analog/digital audio converter and a method thereof

An analog/digital audio converting apparatus enables listening to both digital and analog audio signals received from a digital receiving apparatus and analog audio signals input from an external source using the same receiver by providing a formatter capable of converting the analog audio signal into a digital audio signal with the digital broadcasting receiving apparatus.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §119 of Korean Patent Application No. 2004-90653, filed Nov. 9, 2004, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present general inventive concept relates to an analog/digital audio output apparatus. More particularly, the present general inventive concept relates to an audio output apparatus to enable reception of an analog audio signal in a digital broadcasting receiving apparatus through an external receiver.

2. Description of the Related Art

Audio signals received and processed in a digital broadcasting receiving apparatus comprise AC-3 and moving picture experts group (MPEG) data, which are decoded using a software codec capable of compressing and playing a digital audio signal processed by a digital signal processor (hereinafter, referred to as “digital audio DSP”), or without a dedicated hardware, and analog-processed to be output through a speaker. If being provided with a dedicated external audio/video (AV) receiver, a user can output the AC-3 and the MPEG data received through the digital broadcasting receiving apparatus as a digital signal without causing any loss of the data, connect the digital broadcasting receiving apparatus to the external A/V receiver, decode the digital signal at the digital audio DSP in the external A/V receiver and output the decoded signal through a speaker. Among digital audio interfaces for the above operations, a SONY®/PHILIPS® digital interface (SPDIF) is a prevailing one for domestic use.

The SPDIF has a digital output standard produced by SONY® corporation and ROYAL PHILIPS® Electronics, andFIG. 1schematically shows a block diagram of a conventional digital broadcasting receiving apparatus for processing a digital output of the SPDIF. Referring toFIG. 1, the conventional digital broadcasting receiving apparatus mainly comprises a digital processing part and an analog processing part.

The digital processing part comprises a tuner10for receiving a channel from an external sky wave, a cable, and a satellite, a channel demodulator (demod)20for outputting a transport stream (TS) corresponding to the received channel, a multimedia processor50including a TS demultiplexer (demux), an MPEG decoder and a graphic mixer, a controller (CPU)40for controlling the overall system, and a digital audio DSP60for processing the digital audio. The multimedia processor50outputs an image as a video out signal, a super video (S-video) out signal, or a digital video interactive (DVI) signal.

The digital audio DSP60outputs the SPDIF output (digital out) to the outside or transmits a digital audio signal to a national television system committee (NTSC) audio decoder70so as to enable a user to listen to the digital audio signal through an external speaker.

In general, the conventional digital broadcasting receiving apparatus is able to receive and process conventional analog broadcasting. Here, an audio signal in such a conventional analog broadcasting is in accordance with the NTSC.

The analog processing part comprises an NTSC intermediate frequency (IF) converter or decoder30for converting the channel received by the tuner10into an IF signal and the NTSC audio decoder70for processing the NTSC audio signal, that is, the IF signal. Also, even an externally input audio signal is input to the NTSC audio decoder70so as to be processed to the left or the right according to a user's choice and transmitted as a L/R out signal to the external speaker. The NTSC IF converter30outputs an NTSC video signal to the multi-media processor.

In the conventional digital broadcasting receiving apparatus as described above, the NTSC audio signal is volume-controlled by the NTSC audio decoder70, output to the left or the right and input to the speaker or other external devices, such as a video cassette recorder (VCR) for recording.

The user utilizing the external receiver (not shown) connects the SPDIF output from the digital audio DSP60of the digital broadcasting receiving apparatus to an input terminal of the external receiver and decodes the SPDIF in a digital audio DSP of the external receiver to thereby listen to the sound through the external speaker. Usually, volume of the conventional digital broadcasting receiving apparatus is set to ‘0’ because the volume of the digital broadcasting receiving apparatus is turned down when receiving through the external receiver.

In a case of converting the channel to the NTSC signal or receiving the external input audio signal, such as from the VCR, the audio signal at this time is in the analog form, and therefore, the user needs to turn up the volume of the conventional digital broadcasting receiving apparatus to listen to the sound.

In other words, when the digital broadcasting receiving apparatus is receiving NTSC broadcasting or processing an input from the external VCR, the user who uses a separate receiver having the digital audio DSP suffers an inconvenience of turning up the volume of the conventional digital broadcasting receiving apparatus which is primarily set to ‘0’, in order to listen to the sound through the external speaker.

SUMMARY OF THE INVENTION

The present general inventive concept provides an apparatus capable of converting an analog audio signal to a digital audio signal and outputting the digital audio signal through a SONY®/PHILIPS® digital interface (SPDIF), such that a user who utilizes a dedicated receiver having a digital audio digital signal processor (DSP) therein is able to listen to the analog audio signal through an external speaker.

The foregoing and/or other aspects and advantages of the present general inventive concept may be achieved by providing an analog/digital audio converting apparatus usable with a digital broadcasting receiving apparatus, the analog/digital audio converting apparatus comprising an audio decoder to select and output at least one of input analog audio signals, an output device to separate a digital audio signal from input signals of the digital broadcasting receiving apparatus and to output the separated signal as a first digital audio signal, a formatter to process the analog audio signal output from the audio decoder and to output the processed signal as a second digital audio signal, and a digital audio processing device to select and output one of the first digital audio signal output from the output device and the second digital audio signal output from the formatter.

The digital audio processing device may select and output one of the first and the second digital audio signals according to a selecting signal input externally. Alternatively, the digital audio processing device may select the second digital audio signal output from the formatter upon receiving a signal to select the signal output from the audio decoder.

At least one of the analog audio signals input to the audio decoder may be an analog audio signal output from the digital broadcasting receiving apparatus or an analog audio signal input from an external device. The first and the second digital audio signals may be SONY®/PHILIPS® digital interface (SPDIF) signals.

The formatter may be disposed within the digital audio processor, such that the analog audio signal output from the audio decoder is processed into the second digital audio signal, and one of the first and the second digital audio signals is selectively output.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 2is a block diagram illustrating a digital broadcasting receiving apparatus400according to an embodiment of the present general inventive concept.

Referring toFIG. 2, the digital broadcasting receiving apparatus400comprises a digital processing part100, an analog processing part200, and a formatter300to convert an audio signal output from the analog processing part200into a digital signal and to input the converted signal into the digital processing part100.

The digital processing part100comprises a tuner110to receive a predetermined channel from an external sky wave, a cable, and a satellite, a channel demodulator (demod)120to process an intermediate frequency (IF) corresponding to the channel and to output a transport stream (TS)122, a multimedia processor150including therein a TS demultiplexer (demux), a moving picture experts group (MPEG) decoder, and a graphic mixer, a controller (CPU)140to control the overall system, and a digital audio processor160(hereinafter, referred to as “digital audio DSP”) to receive a first digital audio signal152output from the multimedia processor150and to process the received first digital audio signal152. Here, the multimedia processor150processes and outputs the TS122as an image through a video output or a super-video (S-video) output or as a digital video interactive (DVI) output which is a type of compressed data used to record a moving image as digital data, and separates a digital audio signal from received signals of the TS stream122to output the separated digital audio signal as the first digital audio signal152.

The digital audio DSP160processes and outputs the first digital audio signal152through a SONY®/PHILIPS® digital interface (SPDIF) externally as a digital output signal166, thereby enabling a user who utilizes an external receiver (not shown) to receive and listen to the digital output signal166. More specifically, the SPDIF of the digital audio DSP160can be connected to an input terminal of the external receiver and the digital output signal166can be decoded at a digital audio DSP of the external receiver. Accordingly, the user can listen to sound corresponding to the digital output signal166through an external speaker, such as earphones. Further, the digital audio DSP160is constructed to decode the first digital audio signal152output from the multimedia processor150, separately output the decoded signal as different types of audio data, convert the output audio data into an analog audio signal, synthesize the analog audio signal as a multi-channel audio signal164and output the multi-channel audio signal164to a national television system committee (NTSC) audio decoder270, which will be explained in greater detail below, so that the sound can be listened to through the external speaker.

Also, an analog/digital audio selecting signal162is input an external source to select one of the first digital audio signal152and a second digital audio signal310input from the formatter300. The digital audio DSP160outputs the selected signal as the digital output signal166.

The analog processing part200comprises an NTSC IF decoder230and the NTSC audio decoder270. The NTSC IF decoder230amplifies the IF signal corresponding to the channel received by the tuner110and separates the amplified IF signal into an NTSC audio signal232and an NTSC video signal234. The NTSC IF decoder230outputs the separated NTSC video signal234to the multimedia processor150and the separated NTSC audio signal232to the NTSC audio decoder270. The NTSC audio decoder270receives an input audio selecting signal272, which is to select any one of the separated NTSC audio signal232, an externally-input audio signal220, and the multi-channel audio signal164output from digital audio DSP160, amplifies the audio signal selected by the input audio selecting signal272, and outputs the amplified signal as a left/right (L/R) output signal276, to transmit the left/right (L/R) output signal276to an external speaker. In addition, the NTSC audio decoder270outputs the amplified signal as an NTSC audio signal274to the formatter300in order to digitally convert the selected audio signal.

The formatter300receives the NTSC audio signal274output from the NTSC audio decoder270, processes the NTSC audio signal274to convert the NTSC audio signal274into the second digital audio signal310to be input into the digital audio DSP160. Here, the NTSC audio signal274may be the same as the L/R output signal276output from the NTSC audio decoder270.

The formatter300converts the input NTSC audio signal274into the second digital audio signal310using an analog/digital (A/D) converter, compresses and outputs the second digital audio signal310to the digital audio DSP160, which can output the second digital audio signal310as the digital output signal166according to the analog/digital selecting signal162. The formatter300may have various types of structure to receive and digitally output various analog audio signals. The formatter300may alternatively be disposed inside the digital audio DSP160instead of separately provided, as illustrated inFIG. 2. In other words, the digital audio DSP160can be capable of converting and outputting an input analog audio signal as a digital audio signal, and the NTSC audio signal274output from the NTSC audio decoder270can be directly input to the digital audio DSP160to be processed therein.

In the digital broadcasting receiving apparatus400, as described above, even while the digital output signal166output from the digital audio DSP160externally is received through the external receiver (not shown), if the user selects the analog audio by operating the A/D audio selecting signal162, the digital audio DSP160can select the second digital audio signal310output from the formatter300, thereby enabling the user to digitally listen to the analog audio through the external receiver.

Herein, the second digital audio signal310output from the formatter300corresponds to the selected one of the NTSC audio signal232separated from the NTSC IF decoder230, the externally-input audio signal220, and the multi-channel audio signal164output from the digital audio DSP160, according to the input audio selecting signal272. Thus, the user can select the analog audio signal (NTSC audio signal274) as desired, by operating the input audio selecting signal272.

Accordingly, the formatter300to convert the selected analog audio signal274into the second digital audio signal310enables listening to the selected analog audio signal274or the second digital audio signal through the external receiver as desired by the user, without inconveniences of a conventional digital broadcasting receiving apparatus, such as having to listen to the sound only through the external receiver and change the channel to an analog channel when receiving a digital broadcasting, and having to convert to an internal speaker to connect to an external device, such as video cassette recorder (VCR).

As described above, in a digital outputting apparatus usable with an analog audio signal according to the present general inventive concept, when receiving an analog broadcasting signal through a digital broadcasting receiving apparatus or through an external device, such as VCR, a user utilizing a dedicated receiver including a digital audio DSP therein can receive and listen to sound through an external speaker.