CA2491578C

CA2491578C - Portable karaoke device

Info

Publication number: CA2491578C
Application number: CA2491578A
Authority: CA
Inventors: Kyung Ho Lee
Original assignee: Enter Tech Co Ltd
Current assignee: Enter Tech Co Ltd
Priority date: 2004-12-31
Filing date: 2004-12-31
Publication date: 2011-11-29
Anticipated expiration: 2024-12-31
Also published as: CA2491578A1

Abstract

A portable Karaoke device having a sound module mounted in an ASIC, an external extension pack, a download memory, a musical instrument sound memory, a rendering unit, an amplifier/limiter circuit, a mixer, a low pass filter, an RF
amplifier, a receiver, a data processor, an RGB encoder, an overlay circuit, an internal video transmitter/receiver circuit, an external video transmitter/receiver circuit, an MP3 decoder and a communication interface.

Description

PORTABLE KARAOKE DEVICE
BACKGROUND OF THE INVENTION

Field of the Invention The present invention relates in general to portable karaoke devices, and more particularly to a portable karaoke device which is capable of allowing the user to sing over a main microphone or auxiliary microphone and listen to his song mixed with an accompaniment sound through an audio unit while viewing a background picture with a lyrics caption through a video unit, of temporarily storing a tune downloaded through a moving picture experts group 2 (MPEG 2) layer 3 (MP3) technique or communication interface in its internal sound module to use the stored tune as an accompaniment sound, and of varying the phase and harmony of the accompaniment sound to output a modulated accompaniment sound, so that the user can conveniently and simply use the device with no necessity for replacing a sound memory in which lyrics and accompaniments of newest songs are previously recorded and avideo memory that provides a background picture, a plurality of users can use the device simultaneously, and the user' s song can be stored and then listened later or sent through the Internet in the form of music letter.

Background of the Related Art As well known in the art, accompaniment devices are adapted to store data about accompaniments of a large number of tunes in their internal memories. If the user selects a desired one of the tunes, then the associated accompaniment device outputs a sound of an accompaniment associated with the selected tune through a speaker at the same time that it inputs a song voice of the user through a microphone and outputs it through the speaker. As a result, people can simply practice singing with the accompaniment devices.
However, people have to purchase the above-mentioned accompaniment devices at a great expense and cannot use them at any places other than their installed places, because most of the accompaniment devices basically comprise monitor screens mounted integrally therewith and are usually installed within rooms.

For these reasons, in order to use the accompaniment devices, people must search for places where the accompaniment devices have already been installed.
In order to overcome the above problems, there has been proposed a portable wireless accompaniment system comprising a plurality of expandable read only memory (ROM) packages for assigning numbers respectively to tunes desired by the user and storing accompaniments of the tunes in the form of digital signals.
In the proposed accompaniment system, a microprocessor is operated synchronously with an oscillation frequency from an oscillator and in response to a tune number and other items applied through a key matrix by the user.
The microprocessor is adapted to control the entire system operation according to routines stored in a program memory. Further, the microprocessor stores data related to a played tune in a memory and displays the current operation state on a display unit through a liquid crystal display (LCD) driver.
Further, the microprocessor controls a multiplexer, a D-type flip-flop, a ROM
package and other components in the system in response to a tune selection through the key matrix by the user. A dual sound controller reproduces a stereo accompaniment sound, which is then amplified by an amplifier.
An echo generator is adapted to selectively output an echo sound of mechanical vibration waves. A tone controller controls a tone of the echo sound from the echo generator, which is then mixed with a stereo audio signal from a microphone terminal.
A gain controller controls a gain of the mixed signal and an audio amplifier amplifies the resultant audio signal together with the amplified stereo accompaniment sound from the above amplifier.
A radio frequency (RF) modulator modulates the amplified audio and accompaniment signals at a predetermined radio frequency. As a result, a synthetic melody signal is obtained by mixing the audio signal and accompaniment signal and then transmitted by radio to an external audio unit through an antenna.
As an alternative, there has been proposed a portable wireless video accompaniment system wherein lyrics caption data is outputted to a video unit together with a background video signal at the same time that an accompaniment sound of a selected tune is outputted to an audio unit while being mixed with

-2-a voice inputted through a microphone, thereby allowing the user to sing to the accompaniment sound while viewing lyrics on a background picture. However, the above-mentioned conventional portable wireless accompaniment system and portable wireless video accompaniment system are advantageous in that they can be conveniently carried and used by the user, but have the following disadvantages.
Firstly, the existing ROM packages must be replaced with new ones whenever new tunes are added. Secondly, the user cannot personally select a desired background picture and is thus liable to feel a repugnance toward the same background picture being continuously repeated. Thirdly, the user cannot select or reserve a next tune while singing over a microphone of the system body. As a result, it requires the user to spend extra time manipulating the controls to select or reserve a next tune.

SUMMARY OF THE INVENTION

Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a portable wireless

-3-accompaniment system which is capable of allowing the user to sing over a main microphone or auxiliary microphone and listen to his song mixed with an accompaniment sound through an audio unit while viewing a background picture with a lyrics caption through a video unit, of temporarily storing a tune downloaded through an MP3 technique or communication interface in its internal sound module to use the tune as an accompaniment sound and of varying the phase and harmony of the accompaniment sound to output a modulated accompaniment sound, so that the user can conveniently and simply use the accompaniment system.
In a feature of the present invention, an MP3 decoder and/or a communication interface is provided to download an accompaniment of a desired tune from a server, and an external expandable pack or a sound module and a download memory are provided to store the accompaniment downloaded by the MP3 decoder and/or the communication interface.
A video signal received from a video unit by radio or an internally stored video signal is utilized as a background picture. A video signal mixed with a lyrics caption is transmitted by radio to the video unit so that the user can view the background picture and lyrics.
In addition to a main microphone over which the user sings while listening to an accompaniment sound, there is provided an auxiliary microphone for transmitting a signal by radio or through a cable. The user can select and apply a next tune using the auxiliary microphone while singing over it.
A song mixed with the accompaniment sound is stored in an internal memory of the device and then outputted directly or through the communication interface.
The accompaniment sound is created in such a manner that maximum thirty-two ones among one-hundred-twenty-eight musical instrument sounds are simultaneously mixed. While the accompaniment sound is outputted as a mixed sound, it is modulated in such a manner that the phase and harmony thereof are varied into a desired phase and harmony, Accordingly, with no necessity for replacing a sound memory in which lyrics and accompaniments of newest songs are previously recorded and a video memory in which background pictures are stored, the user can simply and efficiently use the portable Karaoke device of the present invention. Furthermore, a plurality of users can utilize the portable Karaoke device simultaneously. Moreover, the user' s song is stored

-4-i and then listened later or transmitted through the Internet in the form of music letter.

BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
Fig. 1 is a block diagram schematically showing the entire construction of a portable karaoke device in accordance with the present invention;
Fig. 2 is a block diagram schematically showing the construction of an application specific integrated circuit in Fig. 1;
Fig. 3 is a circuit diagram showing the construction of a video signal processing circuit including an RGB encoder, overlay circuit and synchronization output unit in accordance with the present invention;
Fig. 4 is a circuit diagram showing the construction of an accompaniment sound output circuit in accordance with the present invention;
Fig. 5 is a circuit diagram showing the construction of an amplifier/limiter circuit in Fig. 1:
Fig. 6 is a circuit diagram showing the constructions of an output amplifier and radio frequency amplifier in Fig. 1;
Fig. 7 is a circuit diagram showing the construction of a receiver in Fig. 1;
Fig. 8 is a circuit diagram showing the construction of an internal video transmitter/receiver circuit in Fig. 1;
Fig. 9 is a circuit diagram showing the construction of an external video transmitter/receiver circuit in Fig. 1;
Fig. 10 is a circuit diagram showing the construction of an auxiliary microphone in Fig. 1;
Fig. 11 is an exploded perspective view showing the construction for combining the receiver for receiving or transmitting a signal by radio with the sound module according to an embodiment of the present invention; and Fig. 12 is a plan view showing the construction of a signal connector for receiving or transmitting a signal through wire according to another embodiment of the present invention,

5---- - --------DETAILED DESCRIPTION OF THE INVENTION
Fig. 1 is a block diagram schematically showing the entire construction of a portable karaoke device in accordance with the present invention. As shown in this drawing, the karaoke device comprises a sound module 1 mounted in an ASIC
4 for assigning arbitrary numbers respectively to given tunes and storing accompaniments of the tunes and a download memory 2. The sound module 1 has an internal memory la and an extension pack 90. Tunes are stored in the internal memory la and extension pack 90 of the sound module I and the download memory 2 in the form of digital signals such that additional tunes can be stored in therein.
The karaoke device further comprises an application specific integrated circuit (ASIC) 4 including the sound module 1 and a microprocessor that are operated synchronously with an oscillation frequency from a crystal oscillator and in response to a tune number and other items applied through a key matrix 3 by the user.
The microprocessor 31 in the ASIC 4 is adapted to control the entire system operation according to routines stored in a storage unit 5. Further, the microprocessor 31 stores data related to a played tune in a random access memory (RAM) 6 and displays the current operation state on an LCD 7 through an LCD driver (not shown).
The storage unit 5 may preferably include a program memory OS-ROM 5a for storing the routines for the control of the system operation, a character memory FONT-ROM 5b for storing and outputting characters in the form of digital signals, a tune memory DATA-ROM 5c for compressing, storing and outputting music data in a musical instrument digital interface (MIDI) format, and a video memory GRAPHIC-ROM 5d for storing and outputting a video signal in the form of a digital signal.
In response to a tune selection through the key matrix 3 by the user, the microprocessor 31 in the ASIC 4 outputs an accompaniment sound of a corresponding tune stored in the internal sound module 1 the external extension pack 90, or download memory 2 to a rendering unit 8.
A musical instrument sound memory 9 samples 128 musical instrument sounds to convert analog audio signals corresponding to the 128 musical instrument sounds into digital audio signals and stores the digital audio signals. The

-6-i musical instrument memory 9 simultaneously mixes maximum 36 musical instrument sounds among 128 sounds and outputs the mixed sound.
The rendering unit 8 varies the phase and/or harmony of an accompaniment sound transmitted from the sound module 1, the external extension pack 90, or download memory 2 to selectively modulate the accompaniment sound according to the musical instrument sound outputted from the musical instrument sound memory 9 and outputs the modulated accompaniment sound.
The accompaniment sound modulated by the rendering unit 8 is sent to a mixer 10.
A main microphone 11 is adapted to input a users song voice, convert it into an electrical signal and output the resultant audio signal. An amplifier/limiter circuit 12 functions to amplify the audio signal from the main microphone 11 and limit the amplitude of the amplified audio signal to a predetermined level.
The amplified audio signal is mixed with an accompaniment sound by the mixer and then selectively stored in a flash memory 2a.
The audio signal mixed with the accompaniment sound, which is stored in the flash memory 2a and then read or directly outputted, is transmitted through an A-D/D-A converter 13 to a low pass filter 14, which then passes only frequency band components lower than 20KHz to remove sampling noise components higher than 20KHz from the audio signal.
An output amplifier 15 amplifies data of the frequency band components lower than 20KHz from the low pass filter 14 and transfers the resultant audio signal to an RF amplifier 16, which then modulates the audio signal into an RF
signal and transmits the modulated RF signal to an external audio unit by radio through an antenna 17.
An auxiliary microphone 26 is provided separately from the system body A to transmit audio and data signals by radio to the body through a transmission antenna 27. A receiver 19 of the body A is adapted to receive the audio and data signals from the auxiliary microphone 26 through a reception antenna 18 or through a cable 28 and separate the received signals from each other.
The separated audio signal from the receiver 19 is transferred to the amplifier/limiter circuit 12 which also receives the audio signal from the main microphone 11. Then, the amplifier/limiter circuit 12 selectively _7-{

amplifies the audio signal from the receiver 19 and the audio signal from the main microphone 11, and limits the amplitude of the amplified audio signal to the predetermined level as stated previously.
A data processor 20 is adapted to convert the separated data signal from the receiver 19 into a digital signal and transfer the converted digital signal to the ASIC 4. Such a digital signal to the ASIC 4 may preferably include a signal associated with a tune or volume that the user selects or adjusts using the auxiliary microphone 26.
A red (R) green (G) blue (B) encoder 21 is connected to the ASIC 4 to generate a background video signal on the basis of digital R, G and B signals, a digital color carrier signal and digital horizontal and vertical synchronization signals from the ASIC 4.
An overlay circuit 22 is connected to the ASIC 4 to mix a caption video signal from the ASIC 4 with the background video signal from the RGB encoder 21 in an overlay manner to express them as one image.
A synchronization output unit 23 is adapted to selectively output a main clock signal of 21.47727MHz or 22.168095MHz according to a National Television System Committee (NTSC) or Phase Alternation Line (PAL) broadcasting system in response to an external synchronization signal.
An internal video transmitter/receiver circuit 24 is adapted to receive a caption/background-mixed video signal from the overlay circuit 22 and transmit the received video signal as an internal video signal through an internal video transmission/reception antenna 25 at a radio frequency controlled by the user. Further, the internal video transmitter/receiver circuit 24 receives a radio frequency signal through the internal video transmission/reception antenna 25, converts the received radio frequency signal into an intermediate frequency signal, detects an external video signal from the converted intermediate frequency signal and outputs the detected video signal to the ASIC 4.
An external video transmitter/receiver circuit 29 is adapted to transmit or receive a radio frequency signal to or from the internal video transmission/reception antenna 25. The external video transmitter/receiver circuit 29 receives a background video signal from a video reproduction unit 30 such as a VCD, LDP or VCR and transmits the received video signal as the external video signal to the internal video transmitter/receiver circuit 24 through an external video transmission/reception antenna 31 at a radio frequency controlled by a frequency controller. Further, the external video transmitter/receiver circuit 29 receives the radio frequency signal from the internal video transmitter/receiver circuit 24 through the external video transmission/reception antenna 31, converts the received radio frequency signal into an intermediate frequency signal, detects the internal video signal from the converted intermediate frequency signal and outputs the detected video signal to a television (TV) 32.
An MP3 decoder 33 under the control of the ASIC 4 is selectively connected to a personal computer (PC) 34 to download data about an accompaniment sound and lyrics of a new tune and store the downloaded data in the download memory 2 and then output it.
A communication interface 35 that operates under the control of the ASIC 4 is connected to the PC 34 to be selectively linked with a server 37 through a wired/wireless communication network 36 to download data about an accompaniment sound and lyrics of a new tune and store the downloaded' data in the download memory 2, The communication interface 35 transmits the user' s audio signal mixed with the accompaniment sound, stored in the flash memory 2a, to a receiving party through the server 37 as a music letter.
Although not shown, a power supply is provided to supply a direct current (DC) voltage from a battery in the karaoke device or an external DC voltage as a system drive voltage.
Fig. 2 is a block diagram schematically showing the construction of the ASIC 3 in Fig. 1. As shown in this drawing, the ASIC 4 includes the microprocessor 41 for controlling the entire system operation.
A serial port 42 is adapted to input and output data under the control of the microprocessor 41.
A clock generator 43 functions to generate a synchronization signal for system synchronization and other clock signals under the control of the microprocessor 41.
The LCD driver 44 displays the current operation state including a tune number selected by the user on the LCD 7 under the control of the microprocessor 41.
The key matrix 3 includes a tune selection button having numeral keys of 0 to 9 for selecting a tune number desired by the user, a tempo adjustment button for adjusting a tempo of a played tune, a tone adjustment button for adjusting a tone of the played tune, up/down buttons for adjusting the tempo and tone of the played tune to levels desired by the user after the tempo and tone adjustment buttons are pushed by the user, a reset button for returning the played tune to its normal state when the tune is abnormally played due to a glitch in play or a mistake in button operation by the user, and a continuous play button for playing tunes continuously with no separate selection. The key matrix 3 further includes a start button for starting a tune selected by the user, a stop button for stopping the play of the selected tune, and a modulation selection button for selecting modulation of the accompaniment sound. The user can listen to an accompaniment of a desired tune by pushing the start button and change the played tune to a different one or select it again by pushing the stop button. The key matrix 3 further includes a power button for powering on the system, an MP3 selection button for downloading a tune through the MP3 decoder 33, and a communication selection button for downloading a tune from the server 37 or transmitting a tune through the communication interface 35. A key matrix controller 45 is adapted to transfer items selected through the key matrix 3 by the user to the microprocessor 41.
Input/output ports 46 and 47 under the control of the microprocessor 41 function to output data of accompaniment sound from the internal sound module 1, or input and output data of accompaniment sound of the external extension pack 90 or download memory 2.
A RAM 48 is adapted to temporarily store a video signal from the video reproduction unit, received through the internal video transmission/reception antenna 25, under the control of the microprocessor 41.
A video processor 49 processes the video signal stored in the RAM 48 under the control of the microprocessor 41 to generate a background image.
A memory decoder 50 performs read/write operations under the control of the microprocessor 41 to read and write data from/into the RAM 6 and the storage unit 5 provided with the program memory OS-ROM 5a for storing the routines for the control of the system operation, the character memory FONT-ROM 5b for storing and outputting characters in the form of digital signals, the tune memory DATA-ROM 5c for compressing, storing and outputting music data in a MIDI format and the video memory GRAPHIC-ROM 5d for storing and outputting a video signal in the form of a digital signal, as mentioned above.
Fig. 3 is a circuit diagram showing the construction of a video signal processing circuit including the RGB encoder 21, overlay circuit 22 and synchronization output unit 23 in accordance with the present invention.
A synchronization detector 52 is provided to detect the external synchronization signal from the external video signal from the external video transmitter/receiver circuit 29. To this end, the synchronization detector 52 includes a transistor TR1, inverter 12, resistor R4 and capacitor C2, A
synchronization discriminator 51 is adapted to compare a synchronization signal from the ASIC 4 with the external synchronization signal detected by the synchronization detector 52. To this end, the synchronization discriminator 51 includes an inverter 11, diodes D1 and D2, resistors R1, R2 and R3 and a capacitor Cl.
The overlay circuit 22 includes a video switch for receiving the external video signal from the external video transmitter/receiver circuit 29 or the video signal from the RGB encoder 21 as a background video signal and the caption video signal from the ASIC 4 and alternately selecting the received video signals to mix them in an overlay manner and express them as one image.
The RGB encoder 21 is adapted to generate the background video signal on the basis of the digital R, G and B signals, digital color carrier signal and digital horizontal and vertical synchronization signals from the ASIC 4 and output the generated video signal to the overlay circuit 22.
A clock generator 53 is adapted to generate a clock signal associated with the external video signal from the external video transmitter/receiver circuit 29 according to whether the external video signal is an NTSC-type broadcasting signal of 3.59745MHz or a PAL-type broadcasting signal of 4.447619MHz. To this end, the clock generator 53 includes oscillators OSC1 and OSC2 and NAND
gates Nl, N2 and N3.
An analog switch 54 is adapted to select one of PAL, NTSC, external video and internal video modes under the control of the ASIC based on a users selection.
The synchronization output unit 23 is adapted to output a synchronization signal to the ASIC 4 according to the mode selected by the analog switch 54.
Fig. 4 is a circuit diagram showing the construction of an accompaniment sound output circuit in accordance with the present invention.
When the user pushes the modulation selection button to select a modulation mode and then select a modulation type, the microprocessor outputs an accompaniment sound stored in the sound module 1, the extension pack,90 or the download memory 2 to the rendering unit 8.
The musical instrument sound memory 9, which samples 128 musical instrument sounds to convert analog audio signals of the musical instrument sounds into digital audio signals, simultaneously mixes maximum 36 musical instrument sounds and outputs the mixed sound to the rendering unit 8 under the control of the microprocessor.
The rendering unit 8 varies the phase and/or harmony of the accompaniment sound transmitted from the sound module 1, the extension pack 90, or download memory 2 to selectively modulate the accompaniment sound according to a rendering algorithm for changing the phase and/or harmony of the musical instrument sound outputted from the musical instrument sound memory 9 and outputs the modulated accompaniment sound to the mixer 10.
The amplifier/limiter circuit 12 is adapted to amplify an audio signal from the main microphone 11 or auxiliary microphone 26 corresponding to a users song voice and. limit the amplitude of the amplified audio signal to a predetermined level.
The mixer 10 mixes the amplified audio signal with the accompaniment sound.
The mixed sound is selectively stored in the flash memory 2a only when the user requests it through the key matrix 3.
The A-D/D-A converter 13 functions to separate the audio signal mixed with the accompaniment sound into a left stereo signal L-ST and a right stereo signal R-ST.
The low pass filter 14 includes a first filtering part for passing only frequency band components lower than 20KHz to remove sampling noise components higher than 20KHz from the left stereo signal L-ST from the A-D/D-A converter 13, and a second filtering part for passing only frequency band components lower than 20KHz to remove sampling noise components higher than 20KHz from the right stereo signal R-ST from the A-D/D-A converter 13. The first filtering part is provided with resistors R5 and R6, capacitors C3 and C4 and an operational amplifier OP1, and the second filtering part is provided with resistors R7 and R8, capacitors C5 and C6 and an operational amplifier OP2.
The output amplifier 15 includes a first amplification part for amplifying the sampling noise-removed left stereo signal from the low pass filter 14 to a predetermined level and outputting the amplified left stereo signal to a connector 56, and a second amplification part for amplifying the sampling noise-removed right stereo signal from the low pass filter 14 to a predetermined level and outputting the amplified right stereo signal to the connector 56. The first amplification part is provided with a resistor R9, a capacitor C7 and a negative feedback operational amplifier OP3, and the second amplification part is provided with a resistor RIO, a capacitor C8 and a negative feedback operational amplifier OP4. The connector 56 is coupled with a headphone output unit 55 via a cable.
A high-voltage breaker 57 acts to break an external DC voltage or a battery DC
voltage when the DC voltage is inverted in polarity or has an overvoltage level of 1OV or more. To this end, the high-voltage breaker 57 includes a bias resistor Rll, voltage-dividing resistors R12 and R13 and transistors TR2, TR3 and TR4.
A DC-DC converter 58 is provided to convert the DC voltage passed by the high-voltage breaker 57 into a constant voltage of 4V and supply the converted constant voltage to the ASIC 4 and other internal components in the system.
A delay circuit 59 is adapted to delay the supply of the external DC voltage or battery DC voltage for a predetermined period of time to prevent a surge noise component from being applied to the left and right stereo signals at the initial moment that the DC voltage is supplied. To this end, the delay circuit 59 includes resistors R14 and R15, a capacitor C9 and a transistor TR5.
Fig. 5 is a circuit diagram showing the construction of the amplifier/limiter circuit 12 in Fig. 1.
The amplifier/limiter circuit 12 includes an operational amplifier OP5 for receiving and amplifying an audio signal from the main microphone 11, a first noise limiter for limiting a noise component of the audio signal amplified by the operational amplifier OP5 and feeding the resultant audio signal back to the amplifier OP5, and a first noise attenuator for attenuating a noise component from the audio signal amplified by the operational amplifier OP5 and transferring the resultant audio signal to the A-D/D-A converter 13. The first noise limiter is provided with diodes D3 and D4, and the first noise attenuator is provided with diodes D5 and D6, resistors R16 and R17 and an operational amplifier OP6.
The amplifier/limiter circuit 12 further includes an operational amplifier OP7 for receiving an audio signal from the auxiliary microphone 26 through the receiver 19 and amplifying the received audio signal, a second noise limiter for limiting a noise component of the audio signal amplified by the operational amplifier OP7 and feeding the resultant audio signal back to the amplifier OP7, and a second noise attenuator for attenuating a noise component from the audio signal amplified by the operational amplifier OP7 and transferring the resultant audio signal to the A-D/D-A converter 13, The second noise limiter is provided with a resistor R18 and a capacitor CIO, and the second noise attenuator is provided with diodes D7 and D8, resistors R19 and R20 and an operational amplifier OP8.
The amplifier/limiter circuit 12 further includes a signal measurement part for determining whether each of the audio signals from the first and second noise limiters has been inputted from which one of the main and auxiliary microphones 11 and 26 and outputting a signal measurement signal as a result of the determination. To this end, the signal measurement part includes two operational amplifiers OP9 and OP10.
Fig. 6 is a circuit diagram showing the constructions of the output amplifier 15 and RF amplifier 16 in Fig, 1.
The output amplifier 15 includes a first pre-emphasis circuit 60a for enhancing a signal-to-noise (S/N) ratio of the left stereo signal L-ST from the low pass filter 14, a second pre-emphasis circuit 60b for enhancing an S/N
ratio of the right stereo signal R-ST from the low pass filter 14, and a stereo synthesizer 61 for alternately switching the S/N ratio-enhanced left and right stereo signals L-ST and R-ST from the first and second pre-emphasis circuits 60a and 60b to synthesize them into one audio signal. The first pre-emphasis circuit 60a is provided with a resistor R21 and a capacitor C11, and the second pre-emphasis circuit 60b is provided with a resistor R22 and a capacitor C12.
The output amplifier 15 further includes a phase locked loop (PLL) circuit 62 for generating a high-frequency signal, and a frequency modulation (FM) circuit 63 for modulating the audio signal from the stereo synthesizer 61 at a frequency obtained by wired-ORing it with the high-frequency signal from the PLL circuit 62. The FM circuit 63 is provided with resistors R23 and R24, capacitors C13, C14 and C15, a transistor TR6 and a coil L1.
The output amplifier 15 further includes an exciter 64 for amplifying the FM
signal from the FM circuit 63 to remove an interference between oscillation and output stages. The exciter 64 is provided with a capacitor C16, a resistor R25, a transistor TR7 and a coil L2.
The RF amplifier 16 is adapted to amplify power of the FM signal amplified by the exciter 64 and transmit the resultant RF signal externally through the antenna 17. To this end, the RF amplifier 16 includes a diode D9, a resistor R26, capacitors C17 and C18, a transistor TR8 and coils L3, L4 and L5.
Fig. 7 is a circuit diagram showing the construction of the receiver 19 in Fig. 1.
The receiver 19 includes a filter 65 for receiving the audio and data signals from the auxiliary microphone through the reception antenna 18 and filtering the received signals, an amplification IC 66 for amplifying an output signal from the filter 65 to compensate it for a transmission loss, and a local oscillation IC 67 for generating a local oscillating frequency.
A frequency conversion IC 68 converts an output signal from the amplification IC 66 into an intermediate frequency signal of 10.7MHz by wired-ORing it with the local oscillating frequency from the local oscillation IC 67. A
demodulator 69 is adapted to demodulate the intermediate frequency signal from the frequency conversion IC 68 to separate the original signal from a carrier.
To this end, the demodulator 69 includes a resistor R27, a coil L6 and capacitors C19 and C20.
A separation IC 70 separates the original signal from the demodulator 69 into the original audio signal and data signal. A pair of operational amplifiers OP11 and OP12 are adapted to amplify the original audio signal from the separation IC 70 and transfer the amplified audio signal to the amplifier/limiter circuit 12, and a pair of operational amplifiers OP11 and OP12 are adapted to amplify the original data signal from the separation IC 70 and transfer the amplified data signal to the microprocessor 41 in the ASIC 4 via the data processor 20.
Fig, 8 is a circuit diagram showing the construction of the internal video transmitter/receiver circuit 24 in Fig. 1.
The internal video transmitter/receiver circuit 24 includes a transmission/reception IC 71 for receiving the radio frequency signal from the external video transmitter/receiver circuit 29 through the internal video transmission/reception antenna 25. An amplification circuit functions to amplify the radio frequency signal received by the transmission/reception IC
71. To this end, the amplification circuit is provided with resistors R28 and R29, capacitors C21 and C22, a coil L7 and a transistor TR9. An amplification IC 72 amplifies an output signal from the amplification circuit to compensate it for a transmission loss, and a local oscillation IC 73 generates a local oscillating frequency.
The internal video transmitter/receiver circuit 24 further includes a detection IC 74 for converting an output signal from the amplification IC 72 into an intermediate frequency signal by wired-ORing it with the local oscillating frequency from the local oscillation IC 73, detecting the external video signal from the converted intermediate frequency signal and transferring the detected video signal to the ASIC 4.
A frequency generator is adapted to generate a frequency of the caption/background-mixed video signal from the overlay circuit 22 under the control of a frequency controller 75. To this end, the frequency generator includes resistors R30 and R31, coils L8 and L9, capacitors C23 and C24 and a transistor TRIO.
A stereo IC 76 mixes the separated left and right stereo signals L-ST and R-ST
from the A-D/D-A converter 13 into a stereo audio signal. A pair of transistors TR11 and TR12 are adapted to two-step amplify the stereo audio signal from the stereo IC 76, and a pair of transistors TR13 and TR14 are adapted to two-step amplify the caption/background-mixed video signal with the frequency generated by the frequency generator and wired-OR the amplified video signal with the stereo audio signal amplified by the transistors TRI1 and TR12 to mix them.
The internal video transmitter/receiver circuit 24 further includes a filtering circuit for filtering the stereo audio/video-mixed signal from the transistors TR13 and TR14 and transmitting the resultant radio frequency signal through the internal video transmission/reception antenna 24. The filtering circuit is provided with capacitors C24a and C25 and a coil 1,10.
Fig. 9 is a circuit diagram showing the construction of the external video transmitter/receiver circuit 29 in Fig. 1.
The external video transmitter/receiver circuit 29 includes a transmission/reception IC 77 for receiving the radio frequency signal from the internal video transmitter/receiver circuit 24 through the external video transmission/reception antenna 31, an amplification circuit for amplifying the radio frequency signal received by the transmission/reception IC 77, an amplification 1C 78 for amplifying an output signal from the amplification circuit to compensate it for a transmission loss, and a local oscillation IC
79 for generating a local oscillating frequency. The amplification circuit is provided with resistors R32 and R33, capacitors C26 and C27, a coil Lll and a transistor TR15.
A detection IC 80 is adapted to convert an output signal from the amplification IC 78 into an intermediate frequency signal by wired-ORing it with the local oscillating frequency from the local oscillation IC 79 and detect a stereo audio/video-mixed signal from the converted intermediate frequency signal. A demodulation IC 81 functions to demodulate the stereo audio/video-mixed signal detected by the detection IC 70 to separate it into a stereo audio signal and a video signal.
The video transmitter/receiver circuit 29 further includes an operational amplifier OP15 for amplifying a left stereo signal of the stereo audio signal from the demodulation IC 81 and outputting the amplified left stereo signal to the TV 32 through a left audio output terminal AUDIO L, and an operational amplifier OP16 for amplifying a right stereo signal of the stereo audio signal from the demodulation IC 81 and outputting the amplified right stereo signal to the TV 32 through a right audio output terminal AUDIO R.
A video amplification IC 82 is adapted to amplify the video signal from the demodulation IC 81 and output the amplified video signal to the TV 32 through a video output terminal VIDEO OUT.
A frequency generator functions to generate a frequency of the background video signal from the video reproduction unit 30 under the control of a frequency controller 83. To this end, the frequency generator includes resistors R34 and R35, coils L12 and L13, capacitors C28 and C29 and a transistor TR16.
The video transmitter/receiver circuit further includes a pair of transistors TR17 and TR18 for two-step amplifying the video signal with the frequency generated by the frequency generator, and a filtering circuit for filtering the video signal amplified by the transistors TR17 and TR18 and transmitting the resultant radio frequency signal through the external video transmission/reception antenna 31. The filtering circuit is provided with capacitors C30 and C31 and a coil L14.
Fig. 10 is a circuit diagram showing the construction of the auxiliary microphone 26 in Fig. 1.
The auxiliary microphone 26 includes an input unit 84 for inputting a users song voice and outputting a corresponding audio signal, an operational amplifier OP17 for amplifying the audio signal from the input unit 84, a noise removing circuit for removing a noise component from the audio signal amplified by the operation amplifier OP17, and a first amplification circuit for amplifying the noise-removed audio signal from the noise removing circuit.
The noise removing circuit is provided with operational amplifiers OP18 and OP19, NAND gates NA4, NA5 and NA6, resistors R36-R41 and capacitors C32 and C33, and the first amplification circuit is provided with an inverter 13, a resistor R42 and an oscillator OSC4.
The auxiliary microphone 26 further includes a key matrix 3 having a tune selection button having numeral keys of 0 to 9 for selecting a tune number desired by the user, up/down buttons for adjusting a tempo and tone of a played tune to levels desired by the user, a reset button for returning the played tune to its normal state when the tune is abnormally played due to a glitch in play or a mistake in button operation by the user, a continuous play button for playing tunes continuously with no separate selection, a start button for starting a tune selected by the user, and a stop button for stopping the play of the selected tune. The user can listen to an accompaniment of a desired tune by pushing the start button and change the played tune to a different one or select it again by pushing the stop button.
The key matrix 3 further has a power button for supplying power from a battery contained in the auxiliary microphone 26 to components in the microphone, an MP3 selection button for downloading a tune through the MP3 decoder 33, and a communication selection button for downloading a tune from the server 37 or transmitting a tune through the communication interface 35. A key matrix controller 45 acts to recognize an item selected through the key matrix 3 by the user and generate a corresponding data signal, and a second amplification circuit functions to amplify the data signal from the key matrix controller 45. To this end, the second amplification circuit is provided with an inverter 14, a resistor R43 and an oscillator OSC5.
An audio/data mixer is adapted to mix the audio signal and data signal amplified respectively by the first and second amplification circuits. To this end, the audio/data mixer includes resistors R44 and R45, a transistor TR19, capacitors C34 and C35 and inverters 15 and 16.
A frequency generator is adapted to generate a frequency of the audio/data-mixed signal from the audio/data mixer under the control of a frequency controller 85. To this end, the frequency generator includes resistors R46 and R47, coils L15 and L16, capacitors C36 and C37 and a transistor TR20. A pair of transistors TR21 and TR22 are adapted to two-step amplify the audio/data-mixed signal with the frequency generated by the frequency generator and transmit the resultant radio 'frequency signal through the transmission antenna 27.
The auxiliary microphone 26 further includes a power supply for supplying the power from the battery 86 as operating power to the above components in the microphone. The power supply includes a low power alarm circuit composed of an inverter 17 and a diode D10.
FIG. 11 shows the construction for combining the receiver that transmits or receives a signal by radio with the sound module according to an embodiment of the present invention. The portable Karaoke device having a separable communication module includes a main body 100, a wireless auxiliary microphone receiving module 120 for receiving a radio signal transmitted from the auxiliary microphone 26 provided separately from the body 100 and attached/detached to/from the main body 100, an FM transmission module 130 detachably set in the main body 100 to radio-transmit an audio signal outputted from the portable Karaoke device at an FM frequency, and the extension pack 90 detachably set in the main body 100 to additionally store MIDI data about accompaniment sounds and lyrics.
The main body 100 of the portable Karaoke device has a long shape so that the user can easily grip the device to sing. A main microphone grill 101 is placed at the top of the main body 100. A printed circuit board 102 including a control circuit for operating the portable Karaoke device is fixed inside the main body 100.
The key matrix 3 including a plurality of key buttons, electrically connected to the printed circuit board 102, is attached to one side of the central portion of the main body 100. A battery case 103 containing the battery for providing the operation power to the device is formed on the other side of the main body 100.
An accommodation unit 104 for accommodating the extension packs 90, wireless auxiliary microphone receiving module 120 and FM transmission module 130 is formed under the battery case 103.
A plurality of memory connectors 105 are formed at the bottom of the accommodation unit 104. The memory connectors 105 are partially protruded such that they are easily connected with the extension packs 90 and electrically connected to the printed circuit board 102.
The accommodation unit 104 further includes a male connector 106 for connection of the wireless auxiliary microphone receiving module 120 and a male connector 107 for connection of the FM transmission module 130. The male connectors 106 and 107 are partially protruded such that they are easily connected with the modules 120 and 130 respectively. The male connectors 106 and 107 are electrically connected to the printed circuit board 102.
A pair of first guide grooves 108 are respectively formed on both inner walls of the accommodation unit 104 to guide the wireless auxiliary microphone receiving module 120 to set it in its regular position. A pair of second guide grooves 109 are respectively formed on both inner walls of the accommodation unit 104 to guide the FM transmission module 130 to set it in its regular position.
A protrusion 110 having a support groove 111 formed on the top face thereof is formed at the bottom of the main body 100 in such a manner that it is extended from the main body 100. The support groove 111 stably supports a main jack of a signal connecting device.
The signal connecting device is connected to an input/output terminal to provide video and audio signals transmitted from the portable Karaoke device to an external audio unit or a display.
The wireless auxiliary microphone receiving module 120 is fitted in first and second housings 121 and 122 that construct the body of the receiving module 120.
A female connector (not shown) for the receiving module is formed at the bottom side of the second housing 122. The female connector is connected with the male connector 106 for the receiving module to electrically connect the wireless auxiliary microphone receiving module 120 to a signal line of a wireless receiver including a wireless auxiliary microphone receiving circuit that receives a radio signal captured by an antenna wire 112 of the main body from the auxiliary microphone 26, demodulates the radio signal and then separates it into an audio signal and a data signal.
A pair of first guide protrusions 123 are respectively formed on both sides of the second housing 122 in the vertical direction. The first guide protrusions 123 are slid into the first guide grooves 106.
The FM transmission module 130 is fixed inside first and second housings 131 and 132 constructing the body thereof.
A female connector (not shown) for the transmission module is formed at the bottom side of the second housing 132 to be connected with the male connector 107 for the transmission module. The female connector electrically connects the FM transmission module with a signal line of an FM transmission board including a transmission circuit that modulates an audio signal outputted from the portable Karaoke device with a predetermined FM frequency and then radio-transmits the modulated audio signal to an external radio through the antenna wire 112.
A pair of second guide protrusions 133 are respectively formed on both sides of the second housing 132 in the vertical direction. The second guide protrusions 133 are slid into the second guide grooves 107.
A cover 113 is combined with the main body 100 in such a manner that it covers the battery case 103 and accommodation unit 104 to protect the other side of the main body 100. The cover 103 is provided in such a manner that it opens and closes.
Fig. 12 is a plan view showing the construction of the signal connecting device for transmitting or receiving a signal by wire according to another embodiment of the present invention.
When the user wants to practice singing using the portable Karaoke device, he/she connects a main jack 201 of the signal connecting device 200 with the input/output terminal 114 of the main body 100, connects signal jacks 211 of the signal connecting device 200 to an external display device, and couples a power jack 212 to a connector of an external power adapter (now shown).
In the case that the main body 100 of the portable Karaoke device is connected with the display device and power adapter using the signal connecting device 200, power from the power adapter is supplied to the main body 100 through the power jack 212, main jack 201 and input/output terminal 114 so that the portable Karaoke device can be normally operated.
Audio and video signals corresponding to an accompaniment sound and background picture about a tune selected by the user are transmitted to the display device through the input/output terminal 114, main jack 201 and signal jacks 211 so that the user can view the picture and listen to the sound through a speaker.
Accordingly, the user can sing to the associated accompaniment sound with his/her hand gripping the main body 100.
At this time, the audio signal of the user, inputted through the main microphone 11 of the main body 100, is outputted to the speaker of the display device together with the accompaniment sound of the selected tune.
An auxiliary microphone connector 230 connected with the auxiliary microphone 26 through the cable 28 is coupled with an auxiliary microphone jack 220 of the signal connecting device 200 so that another user can select and input a next song number or sing together with the user who uses the main body 100.
That is, an external audio signal outputted from the auxiliary microphone connector 230 of the auxiliary microphone is transmitted to the main body 100 of the device through the auxiliary microphone jack 220, main jack 201 and input/output terminal 114.
The main body 100 amplifies and filters the external audio signal supplied from the auxiliary microphone jack 220 and outputs the amplified and filtered external audio signal to the speaker of the external display device through the input/output terminal 114, main jack 201 and signal jacks 211.
Accordingly, the user who uses the auxiliary microphone and the user who uses the main body 100 can sing together.
The main body 100 of the portable Karaoke device can output a background picture in the form of motion picture instead of a still picture that may bore the user, to interest the user. In this case, an external video jack 240 of the signal connecting device 200 is connected to a video input/output terminal 250 of an external video unit.
When a tape or disk in which motion picture data is recorded is inserted into the external video unit and then played, a motion-picture signal outputted from a video output terminal of the external video unit is transmitted to the main body 100 of the device through the video input/output terminal 250, external video jack 240, main jack 201 and input/output terminal 144.
The main body 100 of the device mixes the motion-picture signal from the external video jack 240 with caption and tempo signals of a tune selected by the user, and outputs the mixed signal to the display device through the input/output terminal 114, main jack 201 and signal jacks 211. Accordingly, the user can sing to the accompaniment sound outputted together with the motion picture with his/her hand gripping the main body 100 of the portable Karaoke device.
As apparent from the above description, the present invention provides a portable karaoke device comprising an expandable sound module and a download memory for storing an accompaniment of a desired tune downloaded by an MP3 decoder and/or a communication interface from a server.
A video signal is received from a video unit by radio and then utilized as a background picture. A video signal mixed with a lyrics caption is transmitted by radio to the video unit so that the user can view the background picture and lyrics.
In addition to a main microphone over which the user sings while listening to an accompaniment sound, there is provided an auxiliary microphone for transmitting a signal by radio or through a cable. The user can select and apply a next tune using the auxiliary microphone while singing over it.
The tune mixed with the accompaniment sound is stored in an internal memory and then outputted directly or via the communication interface.
The device simultaneously mixes maximum 32 musical instrument sounds among available 128 sounds and outputs the mixed sound. The device can vary the phase and harmony of the mixed sound to output a modulated sound. Therefore, with no necessity for replacing a sound memory in which lyrics and accompaniments of newest songs are previously recorded and a video memory that provides a background picture, the user can simply and efficiently use the present device. Furthermore, a plurality of users can simultaneously use the device. Moreover, the user can stores a song he/she sings and then listens to it later or sends the song through the Internet in the form of music letter.
Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

CLAIMS:

1. A portable karaoke device comprising:

a sound module mounted in an ASIC, an external extension pack and a download memory for assigning arbitrary numbers respectively to given tunes and storing accompaniments of the tunes in the form of digital signals and;
the ASIC including a microprocessor and the sound module that are operated synchronously with an oscillation frequency from an oscillator and in response to a tune number applied through a key matrix by the user, the microprocessor in the ASIC being adapted to control the portable Karaoke device operation according to routines stored in a storage unit, the microprocessor storing data related to a played tune in a RAM and displaying the current operation state on an LCD;
a musical instrument sound memory for sampling a plurality of musical instrument sounds, storing the sampled sounds, mixing the sounds and outputting the mixed sound;
a rendering unit for varying the phase and/or harmony of an accompaniment sound of a tune, transmitted from the sound module or download memory, to selectively modulate the accompaniment sound according to a musical instrument sound outputted from the musical instrument sound memory and outputting the modulated accompaniment sound when the user selects the tune through the key matrix under the control of the microprocessor of the ASIC;
an amplifier/limiter circuit for amplifying an audio signal corresponding to a user's song, transmitted over a main microphone, and limiting the amplitude of the amplified audio signal to a predetermined level;
a mixer for mixing the amplified audio signal with the accompaniment sound modulated by the rendering unit;

a low pass filter for receiving the audio signal mixed with the accompaniment sound transmitted thereto directly or via a flash memory, through an A-D/D-A converter and passing only frequency band components lower than 20KHz to remove noise components higher than 20KHz from the audio signal;
an RF amplifier for receiving the frequency band components lower than 20KHz through an output amplifier, modulating the frequency band components into an RF signal and transmitting the modulated RF signal to an external audio unit by radio through an antenna;
a receiver for receiving audio and data signals from an auxiliary microphone through a reception antenna or through a cable, separating the received signals from each other and transmitting the separated signals to the amplifier/limiter circuit;
a data processor for converting the separated data signal from the receiver into a digital signal and transferring the converted digital signal to the ASIC, the digital signal including a signal associated with a tune or volume that the user selects or adjusts using the auxiliary microphone;
an RGB encoder connected to the ASIC to generate a background video signal on the basis of digital R, G and B
signals, a digital color carrier signal and digital horizontal and vertical synchronization signals;
an overlay circuit connected to the ASIC to mix a caption video signal with the background video signal from the RGB encoder in an overlay manner to express the caption video signal and the background video signal as one image;
a synchronization output unit for selectively outputting a main clock signal of 47727MHz or 168095MHz according to a NTSC or PAL broadcasting system in response to an external synchronization signal;

an internal video transmitter/receiver circuit for receiving a caption/background-mixed video signal from the overlay circuit and transmitting the received video signal as an internal video signal through an internal video transmission/reception antenna at a radio frequency controlled by the user, or receiving a radio frequency signal through the internal video transmission/reception antenna, converting the received radio frequency signal into an intermediate frequency signal, detecting an external video signal from the converted intermediate frequency signal and outputting the detected video signal to the ASIC;
an external video transmitter/receiver circuit for transmitting or receiving a radio frequency signal to or from the internal video transmission/reception antenna, the external video transmitter/receiver circuit receiving a background video signal from a video reproduction unit such as a VCD, LDP or VCR and transmitting the received video signal as the external video signal to the internal video transmitter/receiver circuit through an external video transmission/reception antenna at a radio frequency controlled by a frequency controller, the external video transmitter/receiver circuit receiving the radio frequency signal from the internal video transmitter/receiver circuit through the external video transmission/reception antenna, converting the received radio frequency signal into an intermediate frequency signal, detecting the internal video signal from the converted intermediate frequency signal and outputting the detected video signal to a TV;
an MP3 decoder selectively connected to a personal computer to download data about an accompaniment sound and lyrics of a new tune and store the downloaded data in the download memory under the control of the ASIC; and a communication interface connected to the PC to be selectively linked with a server through a wired/wireless communication network to download data about an accompaniment sound and lyrics of a new tune and store the downloaded data in the download memory under the control of the ASIC, the communication interface transmitting the user's audio signal mixed with the accompaniment sound, stored in the flash memory, to a receiving party through the server in the form of a music letter.

2. The portable Karaoke device as set forth in claim 1, wherein, when the user pushes a modulation selection button of the key matrix, the microprocessor of the ASIC recognizes it as a modulation mode and outputs an accompaniment sound stored in the sound module having the internal memory and extension pack or in the download memory to the rendering unit, the musical instrument sound memory, which samples musical instrument sounds to convert analog audio signals of the musical instrument sounds into digital audio signals, simultaneously mixes maximum musical instrument sounds and outputs the mixed sound to the rendering unit under the control of the microprocessor, and the rendering unit varies the phase and/or harmony of the accompaniment sound transmitted from the sound module or download memory to selectively modulate the accompaniment sound according to a rendering algorithm for changing the phase and/or harmony of the musical instrument sound outputted from the musical instrument sound memory and outputs the modulated accompaniment sound to the mixer.

3. The portable Karaoke device as set forth in claim 1, wherein, when the user pushes a communication selection button of the key matrix, the microprocessor of the ASIC
confirms whether or not a current mode is a music letter mode, an accompaniment sound from the sound module or download memory is transmitted to the mixer directly or in the modulated form, the amplifier/limiter circuit amplify an audio signal from the main microphone or auxiliary microphone corresponding to a users song voice and limit the amplitude of the amplified audio signal to a predetermined level, and the amplified audio signal is mixed with the accompaniment sound by the mixer and then stored in the flash memory so that the user listens to the stored sound when he/she wants to or connects to the server through the communication interface, PC and wired/wireless communication network to send it to a receiving part as a music letter.