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RA-920 

RESISTANCE ATTENUATOR 

INSTRUCTION MANUAL 

Summary of Contents for RA-920

Page 1: ...RA 920 RESISTANCE ATTENUATOR INSTRUCTION MANUAL ...

Page 2: ...n t r o l and should give y o u satisfactory a n d dependable operation f o r many years If trouble is encountered or the unit is damaged in transit please contact y o u r dealer or the nearest service station CONTENTS Features 3 Specifications 3 Circuit Description 4 Control Panel 5 Cautions 7 Applications 8 Parts List 11 P C Board 17 Schematic Diagram 19 ...

Page 3: ...setting 3 Frequency Range DC 1 M H z A t t e n u a t i o n Range 0 1 2 1 d B 0 1 d B step I n p u t O u t p u t Impedance 6 0 0 o h m 10 o h m M a x i m u m Input Level 27 d B m or 0 5W or 17Vrms A t t e n u a t i o n A c c u r a c y l k H z Less t h a n 0 2 d B Less than 0 1 d B for 1 d B step range Less t h a n 0 01dB f o r 0 1 d B step range Frequency Characteristic reference f r e q 1 k H z DC...

Page 4: ...the effect of stray capacitance is minimized and the accuracy is further improved Accordingly when the attenuation per step is 6 0 d B the error caused by a single stage T n e t w o r k is 60 e d B but can be reduced to 42 d B see N O T E below if it is divided into t w o stages N O T E V 3 0 2 30 e 2 42 e d B where the accuracy of resistors is The bridge T n e t w o r k is used in the circuit f r...

Page 5: ...CONTROL PANEL Fig 2 5 ...

Page 6: ...d the case for improved accuracy 4 O U T P U T O u t p u t t e r m i n a l The load impedance should be 6 0 0 o h m If this terminal is t o be connected t o a circuit having an impedance very higher t h a n 6 0 0 o h m insert a 6 0 0 o h m resistor between the c o m m o n terminal 5 and the terminal 4 5 C o m m o n terminal f o r o u t p u t side 6 30 d B STEP Dial f o r 0 30 60 d B a t t e n u a ...

Page 7: ...aracteristic error is shown in Table 1 where 100 k H z signal is attenuated t o 100 d B e is the error 3 at 1 k H z of each dial and f is the error of frequency characteristic The overall error depends o n the number o f dials t o be used as explained below I When the dials are set t o 30 d B x 2 6 0 d B 10 d B x 3 3 0 d B 1 dB x 9 9 dB and 0 1 d B x 10 1 d B then the overall error e caused b y ea...

Page 8: ...evel depending on the c o n d i t i o n of oscillator 2 Set the switches t o the B position and read the indication of the voltmeter 3 N e x t set the switches t o the A position Adjust RA 9 2 0 so t h a t the reading on the voltmeter is the same as at the B position T h e reading obtained is t h e gain of the amplifier When a DC amplifier is to be tested be sure t h a t the input level does not e...

Page 9: ...ld level is e Q and the pulse generator o u t p u t is ej e 0 e j X L O G 1 In measurement be sure t h a t t h e pulse frequency is below 100 k H z the signal is properly sheilded and the load impedance is adequate 3 A u d i o m i x i n g Fig 5 By using t w o R A 9 2 0 it is possible t o attenuate t w o individual signals for audio m i x i n g Oscilloscope TRIG Speaker Speaker Fig 4 Fig 5 9 Pulse ...

Page 10: ... b y L 2 and the gain Gi of A is sufficiently large F j R t l L 2 F t 2 L a F 1 L 2 L 2 G F t j and F t 2 are Ft overall noise figure where L 2 is L 2 and L 2 Measurement o f noise should be performed after check ing the circuit system Fig 6 10 Signal generator or noise generator Amplifier under test Variable attenuator Auxiliary amplifier AC voltmeter RA 920 ...

Page 11: ...l orange X 2 Terminal blue Shorting bar H 0 1 2 8 1 7 1 4 H1 2 051 4 02 H 2 5 0 8 2 5 0 4 Packing case individual packing Packing material foamed styrene X 2 Polyethylene bag J 0 2 0 5 0 3 1 5 Rubber leg X 8 K01 0 0 5 8 2 5 K 2 1 0 8 0 8 0 3 K 2 1 0 8 0 9 0 3 K 2 1 0 8 1 0 0 3 K21 0 8 1 1 0 3 Grip Knob for 30 dB step attenuator Knob for 1 0 dB step attenuator Knob for 1 dB step attenuator Knob for...

Page 12: ...06 R 9 2 0 7 3 5 0 5 Metal film 1 126kft 0 5 1 2W R407 R 9 2 0 7 3 3 0 5 Metal film 37 99ft 0 5 1 2W R408 R 9 2 0 7 3 4 0 5 Metal film 563 2ft 0 5 1 2W C A P A C I T O R C402 CM93BD2A132J Mica 1 300pF 10 M I S C E L L A N E O U S J 2 5 2 8 1 9 0 4 Printed circuit board S401 a b S01 1 5 0 2 0 5 Rotary switch PARTS LIST OF X75 1060 00 SCHEMATIC SYMBOL PARTS NO DESCRIPTION R301 R302 R 9 2 0 7 2 8 0 5...

Page 13: ...7 3 0 0 5 Metal film 490 9ft 0 5 1 2W R31 1 R 9 2 0 7 2 7 0 5 Metal film 121 212 0 5 1 2W R312 R 9 2 0 7 3 1 0 5 Metal film 981 812 0 5 1 2W R313 R 9 2 0 7 2 7 0 5 Metal film 121 212 0 5 1 2W R 3 1 4 3 1 5 R 9 2 0 7 3 0 0 5 Metal film 490 9 2 0 5 1 2W R316 R 9 2 0 7 2 7 0 5 Metal film 121 212 0 5 1 2W R317 R 9 2 0 7 3 2 0 5 Metal film 1 054k fl 0 5 1 2W R318 R 9 2 0 7 3 3 0 5 Metal film 37 99A 0 5...

Page 14: ...2W R210 RN14BK2H2050F Metal film 2 0 5 ft 1 1 2W R21 1 RN14BK2H261 1F Metal film 2 61ft 1 1 2W R212 RN14BK2H8660F Metal film 866ft 1 1 2W R213 RN14BK2H4320F Metal film 4 3 2 ft 1 1 2W R214 RN14BK2H2550F Metal film 255ft 1 1 2W R215 RN14BK2H1690F Metal film 169ft 1 1 2W R216 RN14BK2H1 1 8 0 F Metal film 1 18ft 1 1 2W R217 RN14BK2H86R6F Metal film 86 6ft 1 1 2W R218 RN14BK2H66R5F Metal film 66 5ft 1...

Page 15: ...F Metal film 28 712 1 2W R105 RN14BK2H36R5F Metal film 36 52 1 2W R106 RN14BK2H44R2F Metal film 44 2A 1 1 2W R107 RN14BK2H51R1F Metal film 51 1 fl 1 2W R108 RN14BK2H59R0F Metal film 59 0 fl 1 1 2W R109 RN14BK2H68R1F Metal film 68 1 fl 1 1 2W R1 10 RN14BK2H76R8F Metal film 76 8A 1 1 2W R1 1 1 RN14BK2H2612F Metal film 26 1 kfl 1 1 2W R1 12 RN14BK2H8661F Metal film 8 66kfl 1 1 2W R1 13 RN14BK2H4321F ...

Page 16: ...4BK2H7150F Metal film 715ft 1 1 2W R1 19 RN14BK2H5760F Metal film 5 7 6 ft 1 1 2W R120 RN14BK2H51 1 1F Metal film 5 11kft 196 1 2W R 1 2 1 1 2 2 RN14BK2H4870F Metal film 4 8 7 ft 1 1 2W M I S C E L L A N E O U S J 2 5 2 8 2 2 0 4 Printed circuit board S101 a b S01 1 5 0 4 0 4 Rotary switch 16 ...

Page 17: ...P C BOARD X 7 5 1 0 6 0 0 0 17 X 7 5 1 0 5 0 0 0 ...

Page 18: ...18 P C BOARD X 7 5 1 0 7 0 0 0 X 7 5 1 0 8 0 0 0 ...

Page 19: ... Specifications and design are subject to change without notice for improvement RA 920 19 SCHEMATIC DIAGRAM PC1 J25 2819 04 PC2 J25 2820 04 PC3 J25 2821 04 PC4 J25B 2822 04 OUTPUT 60011 INPUT 600I1 ...

Page 20: ...KENWOOD CORPORATION 2 5 1 Chome Shibuya Shibuya ku Tokyo 150 Japan 26410 PRINTED IN JAPAN B50 2828 20 K ...

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