Sherwood RX-772, Service Manual

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Measuring methods in confirmity with IEC standard 315
Measurements condition FM : Radio frequency = 98.0MHz(RDS), 98.1MHz(K)
Audio frequency = 1kHz Reference level = 1mV on ( 75ohms ) Filter = B.P.F at STEREO
Deviation : MONO = ±75kHz, Stereo = ±67.5kHz±7.5kHz
Test Point : TP 1 = 90.0MHz, TP 2 = 98.0MHz, TP 3 = 106.0MHz(RDS)
Test Point : TP 1 = 90.1MHz, TP 2 = 98.1MHz, TP 3 = 106.1MHz(K)
Power supply : 230V / 50Hz(RDS), 220V / 60Hz(K)
● FM SECTION
No. UNIT NOMINAL L/R LIMIT L/R
1 TUNING RANGE LOW ~ HIGH MHz
STEP(RDS) AUTO/Man. kHz
(K) AUTO/Man. kHz
2 USABLE SENSITIVITY TP 1 dBµV
≤
5
≤
12
S/N = 30dB TP 2 dBµV
≤
5
≤
12
TP 3 dBµV
≤
5
≤
12
3 AUTO STOP LEVEL dBµV 20±3 20+14/-10
4 S/N RATIO @1mV MONO dB
≥
70
≥
65
IHF-A FILTER STEREO dB
≥
65
≥
60
5 TOTAL HARMONIC DISTORTION MONO %
≤
0.5
≤
1
STEREO %
≤
0.8
≤
2
6 50dB QUIETING SENS. MONO dBµV
≤
15
≤
25
STEREO dBµV
≤
35
≤
45
7 CHANNEL SEPARATION 100Hz dB
≥
35
≥
30
1kHz dB
≥
35
≥
30
10kHz dB
≥
30
≥
25
8 FREQUENCY RESPONSE AT ±3dB
1kHz=0dB 50
㎲
(RDS), 75
㎲
(K)
9 SPURIOUS RESPONSE dB
≥
76
≥
60
10 IF REJECTION TP 1 dB
≥
80
≥
70
11 IMAGE REJECTION TP 3 dB
≥
46
≥
30
12 AM REJECTION RATIO AT AM 30% dB
≥
60
≥
55
13 OUPUT LEVEL MONO TAPE REC OUT mV 600±150 600±180
100 / 100
Hz 40~14K 50~12.5K
TUNER SECTION
DESCRIPTION
87.5~108
50 / 50