XL-PM11/XM-PM1
1-8
Yes
Yes
Yes
Yes
Yes
No
No
No
No
3. AUDIO OUTPUT (LINE OUT, EARPHONE OUT)
CHECK
SIGNAL WAVEFORM
PIN No. 33,38 of IC9288
DURING PLAY STATE.
;AUDIO SIGNAL?
CHECK
SIGNAL WAVEFORM
PIN No. 1,2 of
EARPHONE JACK
;AUDIO SIGNAL?
REPALCE
EARPHONE JACK
REPALCE
LINE OUT JACK
CHECK
VOLTAGE PIN No. 58
of MICOM
; 0V(LOW)
CHECK
VOLTAGE COLLECTOR
PIN of Q803
; 0V(LOW)
CHECK
SIGNAL WAVEFORM
PIN No. 1,2 of LINEOUT JACK
; AUDIO SIGNAL
REPLACE MICOM
& MAIN PCB ASS'Y
CHECK MUTE
CRCUIT & REPLACE
MAIN PCB ASS'Y
REPLACE
MAIN PCB ASS'Y
ANALOG VR
; MAX
Explanation of MP3
An audio compression format that is part of the MPEG-1 specification, which was standardized by the Moving Picture
Experts Group, a working group of ISO (International Organization for Standardization), in 1992.
MPEG-1, which is used by VideoCDs, etc., refers to the international standard for audio/video compression technology and
its format. The audio part of the standard is known as MPEG-1Audio (ISO/IEC 11172-3).
MPEG-1 Audio is an audio coding system that can efficiently compress sound by discarding frequencies below the range of
human hearing(1), as well as sound which is masked(2). MPEG-1Audio is divided into three layers: Layer 1, Layer 2 and
Layer 3. The higher the Layer number, the higher the compression rate and the better the sound quality.
32 kHz, 44.1 kHz and 48 kHz sampling rates are supported. Monaural and 2-channel stereo can be compressed to 32-448
kbps with Layer 1, 32-384 kbps with Layer 2 and 32-320kbps with Layer 3.
The following is a summary of each Layer:
MP3 (MPEG-1 Audio Layer 3)
Layer 3
To create efficiently compressed audio data that is perceptually the same as the original, the following modes have been added to
Layer 2.
MDCT (Modified Diskrete Cosine Transform) for subdivision of bandwidth.
Huffman coding that assigns the short bit to the data that frequently appears, and the long bit to the data that does not appear
much.
MS (Middle/Side) stereo coding(3) that divides the stereo signal into the sum signal (L+R) and the difference signal (L-R).
(1) The human ear cannot detect sound above or below 3 kHz in the silent situation.
(2) Auditory masking is the phenomenon where low-frequency sound that occurs immediately after a loud sound cannot be heard
by the human ear.
(3) Joint stereo coding that compresses 2 channels separately or recognizes only the scale factor of each channel that is
compressed by monaural encoding is used in Layer 1 and 2.
