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FL8370

1.  3346 CD Player Evaluating Filter x 2 (NF Electronic Instrument)

2.  VP7722 Panasonic Audio Analyzer

3.  Sony YEDS18 Test CD disc

1.  The audio output of the CD player under test is connected to the CD filter L

& R inputs.

2.  The outputs from the filter are connected to the Audio Analyzer.

1.  Set the mode of the filter to ‘ THRU’

2.  Set the mode of Audio Analyzer to ‘ LEVEL’  mode

3.  Select track 2 of the test disc and play the CD disc

4.  The output voltage and gain of the R & L channels are taken by pressing

the respective buttons on the control board of Audio Analyzer.

1.  Set the mode of the filter to reference level mode.

2.  Select the track 3, 4, 5, and 6 of the test disc and run it under ‘ Play’  mode.

3.  Check the output of the R & L Channels

1.  Set the mode of the filter to ‘ DIST/CH-SP’  mode

2.  Set the audio analyzer to ‘ DIST’  mode.

3.  Set the unit of the audio analyzer to ‘ %’  mode

4.  Select the track 2, 4, and 5 on the test disc and run them under ‘ PLAY’

mode

5.  Check the % of each R & L channels

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FL8370

1.  Set the mode of the filter to ‘ S/N’  mode

2.  Play track 2 of the test disc

3.  The unit of the audio analyzer is set to dB mode

4.  Press the S/N key on the control panel of the audio analyzer

5.  Play track 7

6.  Measure the data of S/N ratio

1.  Set the mode of the filter to ‘ D-Range’  mode

2.  Set the audio analyzer to ‘ DIST’  Mode

3.  Set the unit of the audio analyzer to ‘ dB’  mode

4.  Play track 17of the test disc

5.  The dynamic range should be |A| + 60dB

1.  Set the mode of the filter to ‘ DIST/CH-SP’  mode

2.  Set the audio analyzer to ‘ LEVEL’  mode

3.  Play the tracks 8, 9, 10 & 11

4.  The measured results is the difference between L & R channel

1.  Press the ‘ THRU’  button of the CD filter

2.  Play the track 2 of the test disc

3.  Press the ‘ Relative Level’  and make it ‘ ON’

4.  Select the track 12 and 13 and measure the L & R channels value

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FL8370

1.1 RF Amplifier

The optical currents inputted through pins PD1(A+C) and PD2(B+D) are converted into voltages through
I-V amp, and they are added to RF summing amp. The voltage, converted from the photo diode
(A+B+C+D) signal, is outputted through RFO(pin74) and the eye pattern can be checked at this pin.

Figure 4. RF amp circuit

1.2 Focus Error Amp

The output of the focus error amp is the difference between I-V amp(1) output VA and 
RF I-V amp(2) output VB. The focus error bias voltage applied to the (+) of focus error amp can be
changed by output voltage of D/A converter as shown in diagram, so that the offset of focus error amp
can be adjusted automatically by controlling 5 bits counter switches. Focus error bias can be adjusted
from the range of +100mV ~ -100mV by connecting the resistor on pin 63 (FEBIAS).

Figure 5. Focus error amp circuit

note1> VA and VB refer to output signal of PD1 and PD2 I/V amp.
note2> sev-stopb,sev-stop,fe-stopb and fcmpo are internal signals

65

66

-

-

74

-

73

PD1

PD2

RFO

RF-

58K

10K

VA

I-V amp(1)

VC

58K

10K

VB

I-V amp(2)

VC

VC

RF summing amp

63

-

59

-

-

sev-stopb

FEBIAS

sev-stop

32K

32K

<5 Bit Counter>

3K

X1

X2

X4

X8

X16

164K

FE1

160K

4K

fcmpo

vc

FEBIAS

fe-stopb

SW1

VB >

VA >

fe-stopb

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FL8370

1.3 Tracking Error Amp

The optical currents detected from the side photo diode (E and F) pf pick-up are inputted to the E and F
pin and converted into voltage signals by E I-V and F I-V amp. The output of tracking error amp
generates the difference between E I-V AMP and F I-V AMP voltage output.
The E-F balance can be adjusted by modifying the gain of E I-V AMP, and the tracking gain 
can be adjusted automatically by controlling the peak voltage at pin TE2 by micom program.

Figure 6. Tracking error amp circuit

1.4 Focus OK Circuit

The FOK is the output. The focus OK circuit generates a timing window to enable focus servo operation
from focus search status. When the difference of the RFO (pin74)signal and DC coupled signal
IRF(pin75) are above the predefined voltage the Focus OK circuit output (pin40) becomes active(High
output). The predefined voltage is -0.39V

Figure 7. Focus OK circuit

67

-

68

79

I-V  AMP

I-V  AMP

54

55

Balance

F

E

EI

GAIN_UP/DOWN

BAL < 4 : 0 >

GAIN < 3 : 0 >

TE1

LPFT

To  ISTAT

1

3

K

7

5

K

2

2

0

K

1

1

0

K

5

6

K

2

7

K

1

3

K

1

6

K

7

.5

K

3

.3

K

1

.5

K

-

53

TE2

Window Comp

Gain
Window Comp

To  ISTAT

 To TRCNT

74

75

-

-

40

RFO

IRF

FOK

40K

40K

40K

57K

90K

VC+0.625V

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