US007725135B2

(12) United States Patent (10) Patent No.: 7,725,135 B2 Kim et al. (45) Date of Patent: May 25, 2010

(54) MOBILE TERMINAL AND SOUND 5.448,620 A * 9/1995 Gershkovich et al. .... 455/552.1 PRESSURE CONTROL METHOD 5,544,242 A 8, 1996 Robinson 6,070,088 A * 5/2000 Satoh ...... 455,550.1 (75) Inventors: Se Hwan Kim, Suwon-si (KR); Myoung 2006/0217068 A1* 9/2006 Angelopoulos ...... 455,631 Woo Han, Suwon-si (KR) (73) Assignee: Samsung Electronics Co., Ltd (KR) FOREIGN PATENT DOCUMENTS (*) Notice: Subject to any disclaimer, the term of this KR 1020010054215 T 2001 patent is extended or adjusted under 35 KR 1020060059658 6, 2006 U.S.C. 154(b) by 664 days. (21) Appl. No.: 11/726,242 * cited by examiner Primary Examiner Nguyen Vo (22) Filed: Mar. 21, 2007 (74) Attorney, Agent, or Firm The Farrell Law Firm, LLP (65) Prior Publication Data (57) ABSTRACT US 2008/0070531A1 Mar. 20, 2008 (30) Foreign Application Priority Data A mobile terminal and Sound pressure control method using Sound saturation sensing are disclosed. The mobile terminal Sep. 19, 2006 (KR) ...... 10-2006-0090829 has a target digital value of an adequate output Sound pressure level at a maximum volume level. The sound pressure control (51) Int. Cl. method includes: determining a digital value corresponding H04B I/38 (2006.01) to a maximum output sound pressure level of an externally H04M I/00 (2006.01) Sourced audio material, wherein the externally sourced audio HO3G 3/00 (2006.01) material is being replayed for the first time at a preset gain at (52) U.S. Cl...... 455/567; 455/234.1: 381/107 the maximum Volume level; comparing the determined digi (58) Field of Classification Search ...... 455/567, tal value with the target digital value; adjusting, if the deter 455/550. 1, 200. 1, 230, 232.1, 234.1, 234.2: mined digital value is not equal to the target digital value, the 381/94.1, 104, 107 gain so that a digital value corresponding to the adjusted gain See application file for complete search history. is equal to the target digital value; and storing the adjusted gain as a gain value associated with the maximum Volume (56) References Cited level for the externally sourced audio material. U.S. PATENT DOCUMENTS 4,741,018 A 4, 1988 Potratz et al. 21 Claims, 5 Drawing Sheets

O

17

WIREESS COMMUNICATION UNIT

MEMORY UNIT 12 Audio MATERA M TARGET DIGITAL VALE GAINSETTING TABLE U.S. Patent May 25, 2010 Sheet 1 of 5 US 7,725,135 B2

FIG. 1

17

WIRELESS COMMUNICATION UNIT

AD CONVERTER ------23 33 31

U.S. Patent May 25, 2010 Sheet 2 of 5 US 7,725,135 B2

FIG. 2

START

REPRODUCE CEXTERNALLY SOURCEDAUD ATERIAL YES S43

REPLAY FOR NO THE FIRST TIME 2

PERFORMGAIN REPRODUCEUSING GAIN ADJUSTMENT PROCEDURE SETTING TABLE U.S. Patent May 25, 2010 Sheet 3 of 5 US 7,725,135 B2

FIG 3

START S45 REPLAY EXTERNALLY s451 r. SOURCED AUDIO MATERA. ATMAXIMUM VOLUMELEVEL CALCULATEDIGITAL VALUEP / OF MAXIMUM OUTPUT SOUND PRESSUREEVEL S456 AAEA S455 S466 P-M WITH TARGET DIGITAL P>M

INCREASE CODEC GAIN AND DECREASE AMPFER GAIN AND CALCULATE NEW DIGITAL VALUE P1 CALCULATE NEW DIGITAL VALUEP2

S459 S469 OMPARE P1 WITHM OMPARE P2 WTHM

S461 M st MINIMUM MAXIMUM goDEC GAIN AMPLIFERGAN S463 YES S473 INCREASE AMPLIFER GAN DECREASE CODEC GAN AND CALCULATE NEW DIGITAL AND CALCULATE NEW DIGITAL WALUE P1 UNTIL P1 = M VALUE P2 UNTILP2 = M

STORE ADJUSTED GAN VALUE

NGAIN SETTING TABLE AS GAN VALUE ASSOCATED WTH MAXIMUMWOLUMELEVE. S465 SET AND STORE GAIN VALUES S475 ASSOCATED WITH INDIVIDUAL VOLUMELEVESLOWER THAN MAXIMUM VOLUME U.S. Patent May 25, 2010 Sheet 4 of 5 US 7,725,135 B2 FIG. 4A

W

t

FIG. 4B

W

t

FIG. 4C

2 bit U.S. Patent May 25, 2010 Sheet 5 of 5 US 7,725,135 B2 FIG. 5

EXTERNALLY SOURCED EXTERNALLY SOURCED AUDIO MATERAL 1 AUDIO MATERAL 2 ADUSTED GAIN EEE17 20GE M WALUE: 200)

FIG. 6

SOURCED AUDIO MATERA. EXTERNALLY SOURCED AUDIO MATERIAL 1 EXTERNALLY SOURCED AUDIO MATERA 2 US 7,725,135 B2 1. 2 MOBILE TERMINAL AND A SOUND same capable of enhancing signal-to-noise characteristics of PRESSURE CONTROL METHOD an externally sourced audio material. In accordance with an aspect of the present invention, there PRIORITY is provided a sound pressure control method for a mobile terminal that has a target digital value of an adequate output This application claims priority under 35 U.S.C. S 119 to an Sound pressure level at a maximum Volume level, the method application entitled “MOBILE TERMINAL AND SOUND including determining a digital value corresponding to a PRESSURE CONTROL METHOD filed in the Korean maximum output sound pressure level of an externally Intellectual Property Office on Sep. 19, 2006 and assigned Sourced audio material, wherein the externally sourced audio Ser. No. 2006-90829, the contents of which are incorporated 10 material is being replayed for the first time at a preset gain at herein by reference. the maximum Volume level; comparing the determined digi tal value with the target digital value; adjusting, if the deter BACKGROUND OF THE INVENTION mined digital value is not equal to the target digital value, the gain so that a digital value corresponding to the adjusted gain 1. Field of the Invention 15 is equal to the target digital value; and storing the adjusted The present invention relates generally to a mobile termi gain as a gain value associated with the maximum Volume nal and, in particular, to a mobile terminal and a sound pres level for the externally sourced audio material. Sure control method for the same wherein Sound pressure The step of determining a digital value may include recti levels of an audio material are adjusted using Sound Saturation fying an output signal from the externally sourced audio sensing according to characteristics of the mobile terminal. material; and converting the rectified output signal into digital values. 2. Description of the Related Art Preferably, in the step of adjusting the gain at least one of a Given the advances in communication technologies, a user gain of a coder/decoder (codec) and again of an amplifier is in motion can readily carry a mobile terminal and transmit as adjusted. well as receive phone calls at most times and places. In addition to conventional phone call processing, advanced 25 Preferably, the step of adjusting the gain includes increas mobile terminals, including mobile communication termi ing, if the determined digital value is less than the target nals, notebooks, Personal Digital Assistants (PDAs) and por digital value, the codec gain within the adjustment capability table multimedia players, Support various functions such as of the codec so that the difference between the digital value text message and image transmission, Motion Pictures corresponding to the adjusted gain and the target digital value 30 is minimized. In addition, if the difference is not zero, the Experts Group-1 (MPEG-1) audio layer 3 (MP3) file playing, amplifier gain is increased so that the digital value corre ring tone and ring back tone personalization, and gaming. sponding to the further adjusted gain is equal to the target A mobile terminal includes regular audio materials such as digital value. ring tones and melodies, which are Suitably customized to Preferably, the step of adjusting the gain further includes factors such as resonance properties of the mobile terminal, 35 decreasing, if the determined digital value is greater than the the maximum output sound pressure level or stress producible target digital value, the amplifier gain within the adjustment by an embedded speaker. However, externally sourced audio capability of the amplifier so that the difference between the materials such as MP3 files, ring tones and ring back tones digital value corresponding to the adjusted gain and the target that are downloaded from external providers may be not digital value is minimized. In addition, if the difference is not optimized for the mobile terminal, and are reproduced at a 40 Zero, the codec gain is decreased so that the digital value preset gain. corresponding to the further adjusted gain is equal to the When the maximum sound pressure level of an externally target digital value. sourced audio material to be replayed is lower than that of the The sound pressure control method may further include mobile terminal, sound pressure levels of the speaker are low setting and storing gain values associated with individual even at the maximum volume level. When the maximum 45 Volume levels lower than the maximum volume level with Sound pressure level of an externally sourced audio material respect to the gain value associated with the maximum Vol is higher than that of the mobile terminal, raising Volume ume level. Preferably, the gains associated with the individual levels may cause sound distortion due to Sound saturation. An Volume levels lower than the maximum volume level are extended period of reproduction at a Volume level exceeding adjusted through codec gain adjustment. the maximum Volume level overloads the speaker, and may 50 The sound pressure control method may further include cause permanent damage to the speaker. replaying, setting the gain values associated with the Further, uniform reproduction of externally sourced audio individual volume levels, the externally sourced audio mate materials at a preset gain may limit enhancement of signal rial using the set gain values. to-noise characteristics of the individual externally sourced Preferably, the target digital value corresponds to 80% of audio materials. 55 the output sound pressure level at the maximum volume level of a speaker. SUMMARY OF THE INVENTION The sound pressure control method may further include storing, if the determined digital value is equal to the target The present invention has been made in view of the above digital value, the preset gain as a gain value associated with described problems, and an object of the present invention is 60 the maximum volume level for the externally sourced audio to provide a mobile terminal and a Sound pressure control material. method for the same wherein an externally sourced audio In accordance with another aspect of the present invention, material is tuned and reproduced according to resonance there is provided a mobile terminal including a memory unit properties of the mobile terminal and the maximum output for storing a plurality of externally sourced audio materials, a Sound pressure level or stress producible by a speaker. 65 target digital value of an adequate output sound pressure level Another object of the present invention is to provide a at a maximum Volume level for an externally sourced audio mobile terminal and a sound pressure control method for the material, and a gain setting table for the stored externally US 7,725,135 B2 3 4 Sourced audio materials; an audio output unit for generating The control unit 11 controls the overall operation of the Sounds with a preset gain at the maximum Volume level for an mobile terminal 10. In particular, the control unit 11 controls externally sourced audio material selected for replay for the gain adjustment through saturation sensing of an externally first time; a digital value producer for determining a digital Sourced audio material. value corresponding to a maximum output sound pressure The key input unit 13 includes a plurality of keys for level of the selected externally sourced audio material; a controlling operations of the mobile terminal 10, and sends a comparator for comparing the determined digital value with key value associated with a key input by the user to the control the target digital value; a gain adjuster for adjusting, if the unit 11. User commands through the key input unit 13 can be determined digital value is not equal to the target digital related to events for reproduction of externally sourced audio value, the gain so that a digital value corresponding to the 10 materials. adjusted gain is equal to the target digital value; and again The memory unit 15 stores control programs of the por setter for storing the adjusted gain in the gain setting table as table terminal 10, and data resulting from execution of the again value associated with the maximum volume level for control programs. The memory unit 15 stores again adjust the selected externally sourced audio material. ment program for externally sourced audio materials, and The audio output unit may include a coder/decoder (codec) 15 information necessary for and resulting from execution of the for converting the selected externally sourced audio material gain adjustment program. into an analog signal; a Sound chip having an amplifier for The display unit 17 displays various menus and data stored amplifying the analog signal; and a speaker for outputting the in the memory unit 15 on a screen. In particular, the display amplified analog signal. unit 17 displays visual images necessary for executing events The digital value producer may include a rectifier for rec related to reproduction of externally sourced audio materials. tifying the amplified analog signal; and an Analog to Digital The display unit 17 may include Liquid Crystal Display Converter (ADC) for converting the rectified analog signal (LCD) devices. into digital values. The wireless communication unit 19 modulates data to be The gain adjuster may include a codec gain adjuster for transmitted from the control unit 11 into a signal, upconverts adjusting a gain of the codec to change the output Sound 25 the frequency of the modulated signal, and transmits the pressure levels; and an amplifier gain adjuster for adjusting a upconverted signal via an antenna ANT. The wireless com gain of the amplifier to change the output Sound pressure munication unit 19 receives a signal via the antenna ANT. levels. downcoverts the frequency of the received signal, demodu lates the downcoverted signal into data, and sends the 30 demodulated data to the control unit 11. BRIEF DESCRIPTION OF THE DRAWINGS The audio output unit 21 reproduces an audio material 12 stored in the memory unit 15 for output. The audio output unit The above and other objects, features and advantages of the 21 includes a coder/decoder (codec) 25, sound chip 27, and present invention will be more apparent from the following speaker 29. The codec 25 converts the audio material 12 in a detailed description when taken in conjunction with the 35 digital format into an analog signal, and also converts an accompanying drawings, in which: analog signal Such as a voice signal into a digital signal. The FIG. 1 is a block diagram illustrating a configuration of a Sound chip 27 amplifies an analog signal from the codec 25. mobile terminal according to the present invention; and includes an amplifier for amplifying the analog signal. FIG. 2 is a flow chart illustrating a sound pressure control The speaker 29 outputs an amplified analog signal. method using Sound saturation sensing according to another 40 The digital value producer 23 computes digital values of an embodiment of the present invention; amplified analog signal from (namely, digital values of output FIG. 3 is a flow chart illustrating again adjustment proce Sound pressure levels of an externally sourced audio material) dure of the method of FIG. 2; the sound chip 27 to the speaker 29. In particular, the digital FIGS. 4A-4C are graphs that illustrate the computation of value producer 23 produces digital values corresponding to digital values corresponding to output sound pressure levels; 45 Sound pressure levels of an externally sourced audio material FIG. 5 illustrates gain values adjusted at the maximum reproduced with a preset gain at the maximum Volume level. volume level in the procedure of FIG. 3; and The digital value producer 23 includes a rectifier 31 and an FIG. 6 illustrates a gain setting table produced by the Analog to Digital Converter (ADC) 33. The rectifier 31 rec procedure of FIG. 3. tifies a portion of an amplified analog signal. The ADC 33 50 converts the rectified portion of the analog signal into digital values, and sends the digital values to the control unit 11. DETAILED DESCRIPTION OF PREFERRED In particular, the memory unit 15 stores a plurality of audio EMBODIMENTS materials 12, a target digital value M. and again setting table 16. The target digital value M corresponds to an output Sound Hereinafter, preferred embodiments of the present inven 55 pressure level considered adequate (Vmax of FIG. 4C) at the tion are described in detail with reference to the accompany maximum Volume level. The output sound pressure level ing drawings. The same reference symbols identify the same considered adequate is a critical point of Sound saturation, or corresponding elements in the drawings. Detailed descrip and, in the present invention, is an output sound pressure level tions of constructions or processes known in the art may be of a test audio material at 80% of the maximum volume level omitted to avoid obscuring the invention in unnecessary 60 of the speaker 29. The gain setting table 16 includes gain detail. values, in steps of volume levels, set through gain adjustment FIG. 1 illustrates a configuration of a mobile terminal for each externally sourced audio material, as illustrated in according to the present invention. Referring to FIG. 1, the FIG. 6. mobile terminal 10 includes a control unit 11, a key input unit The control unit 11 includes a comparator 22, a codec gain 13, a memory unit 15, a display unit 17, a wireless commu 65 adjuster 24, an amplifier gain adjuster 26, and again setter 28. nication unit 19, an audio output unit 21, and a digital value The comparator 22 compares a calculated digital value that producer 23. corresponds to the maximum output sound pressure level of US 7,725,135 B2 5 6 an externally sourced audio material with the target digital denotes Voltage and t denotes time. The amplified analog value M. If the calculated digital value is equal to the target signal is passed through the rectifier 31 and converted into a digital value M, the gain setter 28 stores a preset gain in the DC signal as shown FIG. 4B. The DC signal is fed to the AD gain setting table 16 as a gain value associated with the converter 33 and converted into digital values. For example, maximum volume level for the externally sourced audio the digital value P may be obtained through 8 KHZ sampling. material. If the calculated digital value is not equal to the The comparator 22 of the control unit 11 compares the target digital value M, the codec gain adjuster 24 and ampli calculated digital value P with the target digital value M in fier gain adjuster 26 performs a gain adjustment operation step S455. Because the externally sourced audio material is until a new digital value corresponding to the adjusted gain usually not optimized for the mobile terminal 10, the calcu becomes equal to the target digital value M. The gain setter 28 10 lated digital value P be than less or greater than the target stores the adjusted gain value at the time when the corre digital value M. sponding digital value is equal to the target digital value M, in If P is equal to M, the gain setter 28 stores the preset gain in the gain setting table 16 as a gain value associated with the the gain setting table 16 as a gain value associated with the maximum volume level for the externally sourced audio maximum volume level in step S465. If P is not equal to M, material. 15 the codec gain adjuster 24 and amplifier gain adjuster 26 The codec gain adjuster 24 alters digital values correspond performs again adjustment operation to make a new digital ing to output sound pressure levels by adjusting the gain of the value P1 or P2 corresponding to an adjusted gain to the target codec 25. The amplifier gain adjuster 26 alters digital values digital value M step S456 or S466. When a calculated digital corresponding to output sound pressure levels by adjusting value PX is made equal to the target digital value M, the gain the gain of the amplifier in the sound chip 27. Although the setter 28 stores the adjusted gain in the gain setting table 16 as amplifier gain adjuster 26 is included in the control unit 11 in a gain value associated with the maximum Volume level in FIG. 1, it may also be separately installed outside the control step S465. unit 11. For gain adjustment, step S456 is performed when the FIG. 2 is a flow chart illustrating a sound pressure control calculated digital value P is less than the target digital value method using Sound saturation sensing according to another 25 M, and step S466 is performed when P is greater than M. embodiment of the present invention. Referring to FIGS. 1 Digital values are changed through codec gain adjustment and 2, the sound pressure control method is described as and amplifier gain adjustment. follows. In the case when the initially calculated digital value P is When the user enters a replay request for an externally less than the target digital value M in step S456, the codec Sourced audio material through the key input unit 13 in step 30 gain adjuster 24 increases the codec gain in step S457. The S41, the control unit 11 determines whether the requested comparator 22 compares a new digital value P1 correspond externally sourced audio material has been reproduced in step ing to the adjusted gain with the target digital value Min step S43. If the externally sourced audio material has not been S459. If P1 is equal to M, the gain setter 28 stores the adjusted reproduced, the control unit 11 performs again adjustment gain in the gain setting table 16 as again value associated with procedure for the externally sourced audio material in step 35 the maximum volume level in step S465. If P1 is not equal to S45. If the externally sourced audio material has been repro M, the codec gain adjuster 24 determines whether the duced, the control unit 11 replays the externally sourced increased codec gain is equal to the maximum codec gain in audio material using again setting table 16 in step S47. step S461. In the present embodiment, although an externally sourced If the increased codec gain is not equal to the maximum audio material is gain-adjusted at the time of replay for the 40 codec gain, steps S457 and S459 are repeated until the first time, the user may force an externally sourced audio increased codec gain becomes equal to the maximum codec material that has been gain-adjusted to undergo new gain ga1n. adjustment. After the increased codec gain becomes equal to the maxi FIG. 3 is a flow chart illustrating the gain adjustment pro mum codec gain, the amplifier gain adjuster 26 increases the cedure of step S45 of the method of FIG. 2: FIGS. 4A-4C are 45 amplifier gain so as to make a digital value P1 corresponding graphs that illustrate computation of digital values corre to the adjusted gain equal to the target digital value Min step sponding to output sound pressure levels: FIG. 5 illustrates S463. The gain setter 28 stores the adjusted gain in the gain gain values adjusted at the maximum Volume level in the setting table 16 as again value associated with the maximum procedure of FIG. 3; and FIG. 6 illustrates again setting table volume level in step S465. produced by the procedure of FIG. 3. The target digital value 50 In the gain adjustment to increase digital values for the M is stored in the memory unit 15. Referring to FIGS. 1 to 6, output Sound pressure, the codec gain is increased first in the gain adjustment procedure is described as follows. order to prevent signal-to-noise characteristics of an exter The control unit 11 controls the audio output unit 21 to nally sourced audio material from degrading. An increase in reproduce the externally sourced audio material with a preset gain tends to degrade signal-to-noise characteristics of an gain at the maximum volume level in step S451. That is, the 55 audio material, and an increase in codec gain has less adverse control unit 11 sends the externally sourced audio material impact on signal-to-noise characteristics than an increase in stored in the memory unit 15 to the codec 25. The codec 25 amplifier gain. converts the externally sourced audio material in a digital Referring to FIG. 5, for a first externally sourced audio format into an analog signal, and sends the analog signal to material, an initially calculated digital value P of 180 with a the sound chip 27. The sound chip 27 amplifies the analog 60 preset gain of 17 is less than the target digital value M of 200. signal, and outputs the amplified analog signal to the speaker The codec gain is increased first and then the amplifier gain is 29. increased, to make a new digital value corresponding to the During replay, the digital value producer 23 calculates a adjusted gain equal to M of 200. As a result, the preset gain of digital value P of the maximum output sound pressure level in 17 is adjusted to a gain of 20 at the maximum volume level. the amplified analog signal from the Sound chip 27 to the 65 In the case when the initially calculated digital value P is speaker 29 in step S453. Referring to FIG. 4, the amplified greater than the target digital value M in step S466, the ampli analog signal is an AC signal as shown FIG. 4A, in which V fier gain is decreased first and then the codec gain is increased US 7,725,135 B2 7 8 in order not to degrade signal-to-noise characteristics of an reproduction according to resonance properties of the mobile externally sourced audio material. terminal and the maximum sound pressure level and stress The amplifier gain adjuster 26 decreases the amplifier gain producible by the speaker. Further, in setting again value at to calculate a new digital value P2 corresponding to the the maximum Volume level, the codec gain is increased first adjusted gain in step S467. The comparator 22 compares the when the gain is increased and the amplifier gain is decreased digital value P2 with the target digital value Min step S469. first when the gain is decreased, to enhance signal-to-noise If P2 is equal to M, the gain setter 28 stores the adjusted gain characteristics of the externally sourced audio material. corresponding to the digital value P2 in the gain setting table While exemplary embodiments of the present invention 16 as again value associated with the maximum Volume level have been shown and described in this specification, it will be in step S465. If P2 is not equal to M, the amplifier gain 10 understood by those skilled in the art that various changes or adjuster 26 determines whether the decreased amplifier gain modifications of the embodiments are possible without becomes equal to the minimum amplifier gain in step S471. departing from the spirit and scope of the invention as defined If the decreased amplifier gain is not equal to the minimum by the appended claims. amplifier gain, steps S467 and S469 are repeated until the What is is: decreased amplifier gain becomes equal to the minimum 15 1. A sound pressure control method for a mobile terminal amplifier gain. that has a target digital value of an adequate output Sound After the decreased amplifier gain becomes equal to the pressure level at a maximum volume level, the method com minimum amplifier gain, the codec gain adjuster 24 decreases prising: the codec gain so as to make a new digital value P2 corre determining a digital value corresponding to a maximum sponding to the adjusted gain equal to the target digital value output sound pressure level of an externally sourced M in step S473. The gain setter 28 stores the adjusted gain audio material, wherein the externally sourced audio corresponding to the digital value P2 in the gain setting table material is being replayed for a first time at a preset gain 16 as again value associated with the maximum Volume level at the maximum Volume level; in step S465. comparing the determined digital value with the target Referring to FIG. 5, for a second externally sourced audio 25 digital value; material, an initially calculated digital value P of 220 with a adjusting, if the determined digital value is not equal to the preset gain of 17 is greater than the target digital value M of target digital value, the gain so that a digital value cor 200. The amplifier gain is decreased first and then the codec responding to the adjusted gain is equal to the target gain is decreased so as to make a digital value P2 correspond digital value; and ing to the adjusted gain equal to M of 200. As a result, the 30 preset gain of 17 is adjusted to a gain of 14 at the maximum storing the adjusted gain as again value associated with the volume level. maximum volume level for the externally sourced audio After setting the gain value for the maximum Volume level, material. the gain setter 28 sets gain values associated with individual 2. The sound pressure control method of claim 1, wherein Volume levels lower than the maximum volume level with 35 the determining a digital value step comprises: respect to the gain value at the maximum Volume level, and rectifying an output signal from the externally sourced stores the set gain values in the gain setting table 16 in step audio material; and S475. The gain values associated with individual volume converting the rectified output signal into digital values. levels lower than the maximum volume level are set through 3. The sound pressure control method of claim 2, wherein codec gain adjustment for enhancement of signal-to-noise 40 in the adjusting the gain step at least one of a gain of a characteristics of the externally sourced audio material. coder/decoder (codec) and again of an amplifier is adjusted. FIG. 6 illustrates a gain setting table 16, in which five 4. The sound pressure control method of claim 3, wherein volume levels are used. For the first externally sourced audio the adjusting the gain step comprises increasing, if the deter material, an adjusted gain value is 20 at the maximum volume mined digital value is less than the target digital value, the level of 5, and gain values of 17, 13, 8 and 2 are set at volume 45 codec gain so that the difference between the digital value levels of 4, 3, 2 and 1, respectively. For the second externally corresponding to the adjusted gain and the target digital value Sourced audio material, an adjusted gain value is 14 at the is minimized. maximum volume level of 5, and gain values of 12, 8, 5 and 1 5. The sound pressure control method of claim 4, wherein are set at volume levels of 4, 3, 2 and 1, respectively. the adjusting the gain step further comprises increasing, if the Thereafter, when an externally sourced audio material that 50 difference is not Zero, the amplifier gain so that the digital has been gain-adjusted is requested for replay, the externally value corresponding to the further adjusted gain is equal to the Sourced audio material is reproduced according to the target digital value. adjusted gain values stored in the gain setting table 16, unlike 6. The sound pressure control method of claim 3, wherein a conventional reproduction method using a preset fixed gain. the adjusting the gain step further comprises decreasing, if the As apparent from the above description, the present inven 55 determined digital value is greater than the target digital tion provides a mobile terminal and a sound pressure control value, the amplifier gain so that the difference between the method for the same. When an externally sourced audio mate digital value corresponding to the adjusted gain and the target rial is reproduced for the first time, again adjustment opera digital value is minimized. tion is performed, whereby a digital value of the maximum 7. The sound pressure control method of claim 6, wherein output sound pressure level is made equal to a target digital 60 the adjusting the gain step further comprises decreasing, if the value that is set by Saturation sensing of the mobile terminal difference is not Zero, the codec gain so that the digital value and adjusted gain values are saved. After gain adjustment, the corresponding to the further adjusted gain is equal to the externally sourced audio material is reproduced using target digital value. adjusted gain values. As a result, the gain of the output Sound 8. The sound pressure control method of claim 2, wherein pressure of the externally sourced audio material is adjusted 65 the target digital value corresponds to 80% of the output with respect to a sound saturation state of the mobile terminal, sound pressure level at the maximum volume level of a thereby tuning the externally sourced audio material for speaker. US 7,725,135 B2 10 9. The sound pressure control method of claim 1, further 14. The mobile terminal of claim 13, wherein the audio comprising setting and storing gain values associated with output unit comprises: individual volume levels lower than the maximum volume a coder/decoder (codec) for converting the selected exter level with respect to the gain value associated with the maxi nally sourced audio material into an analog signal; mum volume level. 5 a sound chip having an amplifier for amplifying the analog 10. The sound pressure control method of claim 9, wherein signal; and the gains associated with the individual volume levels lower a speaker for outputting the amplified analog signal. than the maximum Volume level are adjusted through codec 15. The mobile terminal of claim 14, wherein the digital gain adjustment. value producer comprises: 11. The sound pressure control method of claim 10, further 10 a rectifier for rectifying the amplified analog signal; and comprising replaying, after setting the gain values associated an analog to digital converter (ADC) for converting the with the individual volume levels, the externally sourced rectified analog signal into digital values. audio material using the set gain values. 16. The mobile terminal of claim 14, wherein the gain 12. The sound pressure control method of claim 1, further adjuster comprises: comprising storing, if the determined digital value is equal to 15 a codec gain adjuster for adjusting again of the codec to the target digital value, the preset gain as a gain value asso change output sound pressure levels; and ciated with the maximum volume level for the externally Sourced audio material. an amplifier gain adjuster for adjusting again of the ampli 13. A mobile terminal comprising: fier to change the output Sound pressure levels. a memory unit for storing a plurality of externally sourced 17. The mobile terminal of claim 16, wherein if the deter audio materials, a target digital value of an adequate mined digital value is less than the target digital value, the output Sound pressure level at a maximum Volume level codec gain adjuster increases the codec gain so that the dif for an externally sourced audio material, and a gain ference between the digital value corresponding to the setting table for the stored externally sourced audio adjusted gain and the target digital value is minimized. materials; 25 18. The mobile terminal of claim 17, wherein if the differ an audio output unit for generating Sounds with a preset ence is not Zero, the amplifier gain adjuster increases the gain at the maximum Volume level for an externally amplifier gain so that the digital value corresponding to the sourced audio material selected for replay for a first further adjusted gain is equal to the target digital value. time; 19. The mobile terminal of claim 16, wherein if the deter a digital value producer for determining a digital value 30 mined digital value is greater than the target digital value, the corresponding to a maximum output sound pressure amplifier gain adjuster decreases the amplifier gain so that the level of the selected externally sourced audio material; difference between the digital value corresponding to the a comparator for comparing the determined digital value adjusted gain and the target digital value is minimized. with the target digital value; 20. The mobile terminal of claim 19, wherein if the differ again adjuster for adjusting, if the determined digital value 35 ence is not Zero, the codec gain adjuster decreases the codec is not equal to the target digital value, the gain so that a gain so that the digital value corresponding to the further digital value corresponding to the adjusted gain is equal adjusted gain is equal to the target digital value. to the target digital value; and 21. The mobile terminal of claim 13, wherein the target again setter for storing the adjusted gain in the gain setting digital value corresponds to 80% of the output sound pressure table as again value associated with the maximum Vol 40 level at the maximum volume level of the speaker. ume level for the selected externally sourced audio material. k k k k k