Yamaha M7CL-32, Руководство по обслуживанию

Страница: 120 / 375

M7CL-32/M7CL-48
120
(1) Gain (2TR OUT DIGITAL)
(2) f characteristic (2TR OUT DIGITAL)
Parameters: 1 kHz is used as the reference of the permissible range.
(3) Distortion factor (2TR OUT DIGITAL)
3-2. PLL Operating Range of WORD CLOCK IN
Parameters: Use System Two.
Use OMNI OUT 15 (L) when measuring L channel.
Use OMNI OUT 16 (R) when measuring R channel.
Select WC IN for WORD CLOCK.
Input from CH1 IN.
Set GAIN to +10 dB.
A. 48 kHz+6 % (50.88 kHz)
Parameters: Set the frequency of the oscillator to 48 kHz + 6%.
(1) Distortion factor (WORD CLOCK IN)
B. 44.1 kHz–10 % (39.69 kHz)
Parameters: Set the frequency of the oscillator to 44.1 kHz –10%.
(1) Distortion factor (WORD CLOCK IN)
3-3. Jitter Measurement
Parameters: Use System Two.
Select Sec, PK.
BW: Select 700 Hz to 100 kHz.
Use 2TR OUT DIGITAL for the inspection.
A. WORD CLOCK INT
Parameters: Select the values in the following table for WORD
CLOCK.
(1) Jitter
B. WORD CLOCK EXT
Parameters: Select WC IN for WORD CLOCK.
When testing, set the frequency of the oscillator as
given in the table below.
A. GAIN MAX
(1) Gain
(2) f characteristic
Parameters: 1 kHz is used as the reference of the permissible range.
(3) Distortion factor
(4) Noise level EIN
Parameters: Short TALKBACK IN with 150
Ω
.
If the measured value is out of the above permissible range,
check for:
Measured value – (gain at 1 kHz) –128
B. GAIN MIN
(1) Gain
(2) Distortion factor
(3) Noise level
Parameters: Short TALKBACK IN with 150
Ω
.
C. Phantom voltage
With No.2 and No.3 pins of XLR shorted and 10 k
Ω
load
connected between No.2 and No.1 pins, adjust the voltage when
the +48 key is turned on as follows.
Also, check that discharging starts immediately when the +48
key is turned off.
3. DIGITAL OUT Characteristic Inspection
3-1. 2TR OUT DIGITAL
Parameters: Use System Two.
Input from CH1 IN.
Set GAIN to +10dB.
A. WORD CLOCK INT48 kHz
Parameters: Adjust WORD CLOCK to INT 48 kHz.
Input Frequency Input Level Prescribed Output Level Permissible Range
1 kHz –60 dBu +4 dBu +4
±
2 dBu
Input Frequency Output Level Permissible Range
1 kHz +22 dBu 0.02 % or below
Input Frequency Input Level Permissible Range
20 Hz –60 dBu –1.5 — 0.5 dB
20 kHz –60 dBu –1.5 — 0.5 dB
Permissible Range
–64 dBu or below
<
=
Input Frequency Input Level Prescribed Output Level Permissible Range
1 kHz –16 dBu +4 dBu +4
±
2 dBu
Input Frequency Output Level Permissible Range
1 kHz +22 dBu 0.01 % or below
Permissible Range
–80 dBu or below
Permissible Range
DC33 — 37 V
Input Frequency Input Level Prescribed Output Level Permissible Range
1 kHz +10 dBu –20 dBu –20
±
2 dBFS
Input Frequency Output Level Permissible Range
1 kHz –2 dBFS 0.002 % or below
Input Frequency Input Level Permissible Range
20 Hz +10 dBu –1.0 — 0.5 dB
20 kHz +10 dBu –1.0 — 0.5 dB
Input Frequency Output Level Permissible Range
1 kHz +22 dBu 0.01 % or below
Input Frequency Output Level Permissible Range
1 kHz +22 dBu 0.02 % or below
WORD CLOCK Permissible Range
INT44.1 kHz 2 nsec or below
INT48 kHz 2 nsec or below