HP-350C-350D-Manual 电路图.pdf

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1、I . : HP Archive . . This vintage Hewlett Packard document was preserved and distributed by www. Please visit us on the web ! . . On-line curator: Tony Gerbic RadioFans.CN 收音机爱 好者资料库 ATTENUATOR SET RadioFans.CN 收音机爱 好者资料库 OPERATING AND SERVICE MANUAL MODEL 350C/D SERIALS PREFIXED: 220- ATTENUATOR SE

2、T Copyright Hewlett-Packard Company 1962 Box 301, Loveland, Colorado 01 307 -1 Printed: OCT 1962 RadioFans.CN 收音机爱 好者资料库 Model 350C/D “able of Contents Lists of Illustrations and Tables TABLE OF CONTENTS Section page I GENERALWFORMATION * - * * - * 1-1 1-1. Introduction. . . . . - . . . . . 1-1 1-2.

3、 Difference Between Models 350C and 35OD . . . . . . . . . . . 1-1 1-4. Description . . . - . . . . . . 1-1 1-7. Uses . . . . . . . . . . . . . . 1-1 1-9. Differences Between Instruments . 1-1 D PREPARATIONFORUSE * - * - 2-1 2-1. InitialInspection . . . . . . - . 2-1 2-3. Repackaging for Shipment. .

4、 . . . 2-1 2-5. Rack/Bench Installation . . . . . 2-1 m OPERATINGINSTRUCTIONS - - . * 3-1 3-1. Operating Considerations . . . . . 3-1 3 -2. Impedance . . . . . . . . . . . 3 - 1 3-4. Leads and Connections . . . . . 3-1 3-6. Input Power Limitation . . . . . 3-1 3-8. Operating Procedures . . . . . . 3

5、-3 3-9. Matched Impedance . . . . . . . 3-3 3-12. Use of Impedance-Matching Network . . . . . . . . . . . 3 -3 Section w e IV PRINCIPLES OF OPERATION 4-1 4-1. General . . . . . . . . . . . . . 4-1 4-3. Attenuation Expressed in Decibels. . 4-1 4-4. Power andVoltageRatios . . . . . 4-1 4-7. Reference

6、for DB . . . . . . . . 4-1 V MAINTENANCE. - - . . . . 5-1 5-1. Introduction . . . . . . . . . . . 5-1 5-3. Instrument Cover Removal . . . . . 5-1 5-5. Component Replacement- . . . . . . 5-1 5-6. Removal of Attenuators . . . . . . 5-1 5-8. Replacement of Resistors . . . . . 5-1 5-10. DC Performance C

7、heck . . . . . . 5-1 5-11. Test Equipment . . . . . . . . . 5-1 5-13. Test Procedure . . . . . . . . . 5-1 5-15. AC Calibration and Accuracy . . . . 5-4 VI REPLACEABLE PARTS * * * * * - * 6-1 6-1. Introduction . . . . . . . . - . . 6-1 6-4. Ordering Information . . . . . . . 6-1 LIST OF ILLUSTRATION

8、S Number Title page Number Title page 1-1. Model 350D Attenuator Set . . . . . . 1-0 5-1. Cabinet Removal . . . . . . . . . . . 5-0 3-1. Model 350C/D Typical Applications. . . 3-2 Removed). . . . . . . . . . . . . . 5 - 1 3-2. Model350CMatchingNetwork . . . . . 3-3 5-3. Assembly A1 Component Identif

9、ication. . 5-2 3-3. Model350DMatchingNetwork . . . . . 3-4 5-4. Assembly A2 Component Identification. . 5-3 5-5. Test Setup for DC Performance Check. . 5-4 4-1. Model 350C/D Simplified Circuit . . . . 4-1 5-6. Model 350C/D Schematic Diagram . . . 5-5 5-2. Model 350C/D Rear View (Rear Panel LIST OF T

10、ABLES Number Title Page 1-1. Specifi from 100 kc to 1 Mc, error is less than k0.25 db at any step. ACCURACY, 100-DB SECTION: From dc to 100 kc, error is less than *0.25 db at any step up to 70 db, less than *0.5 db above 70 db; from 100 kc to 1 Mc, error is less than k0.5 db at any step up to 70 db;

11、 less than *0.75 db above 70 db. POWER CAPACITY: 350C, 500 ohms: 5 watts (50 vdc or rms) 350D, 600 ohms: 5 watts (55 vdc or rms) maximum, continuous duty maximum, continuous duty DIMENSIONS: Module 6-3/32 in. high, 5-1/8 in. wide, 8 in. deep WEIGHT: Net 5 lb, shipping 7 lb 01307-1 1-1 Section I I re

12、fer to the warranty page in this manual. 2-3. REPACKAGING FOR SHIPMENT. 2-4. When returning an instrument to the Hewlett- Packard Company, use the original packing materials (if foam) or contact your authorized Engineering Representative for assistance. Original packing materials which are cardboard

13、 “accordion-like” filler are not recommended for reshipment packing since the useful cushioning qualities are usually gone after one use. If the foam-type packing material is not available, first protect the instrument surfaces with heavy paper or with sheets of cardboard placed flat against the ins

14、trument. Then protect the instrument on all sides (use approximately 4 inches of new packing material designed specifically for packaging cush- ioning), pack in a durable carton marked clearly for proper handling, and insure adequately before shipping. Ship the instrument to the Customer Service dep

15、art- ment at the address given on the warranty page. Note When an instrument .is being returned to for service or repair, attach a tag to the instrument specifying owner, desired action, model number, and full serial number. All correspondence should identify the instru- ment by model number and the

16、 full (eight- digit) serial number. 2-5. RACK / B E N CH I NOT A LLATION 2-6. The Model 350C/D is initially shipped with the plastic feet and tilt stand attached, ready for use as a bench-type instrument (unless ordered specifically as a rack-type model). The instrument may be adapted to mount in a

17、standard 19-inch rack, alone or alongside other modular instruments. Refer to figure 5-1 to see how the feet (and covers) are removed from the instrument. Complete information on rack-mounting the Model 350C/D is available fromyour Engineering Representative or Customer Service. Specify the instrume

18、nt and complete serial number. SECTION 111 OPERATING INSTRUCTIONS 3-1. OPERATING CONSIDERATIONS. 3-2. IMPEDANCE. 3-3. For full accuracy and ease of application, the source and load impedances should match the imped- ance at the INPUT and OUTPUT terminals of the Model 350C/D. When source and load imp

19、edances are the same as the impedance of the Model 350C/D, the amount of attenuation in the circuit is the sum of the two attenuator-knob settings. If an impedance- matching network is used (see paragraph 3-12), the amount of insertion loss must be added to the Model 350C/D setting to obtain the amo

20、unt of attenuation between source and load. 3-4. LEADS AND CONNECTIONS. 3-5. When making connections to the Model 350C/D and the other instruments in the test or measurement setup, use shielded (coaxial) leads as short in length 01307-1 as possible. Failure to use shielded leads may result in attenu

21、ation of a different value from that set on the Model 350C/D controls, especially at high attenuator settings and at frequencies above 100 kc. The shunting effect of stray capacitance (leads, terminals, etc.) is a factor at high frequencies unless shielded connections and short lead lengths are used

22、. Three connectors at the INPUT terminals allow an ac input to be at a dc potential. Connect all inputs to the top and lower left INPUT terminals. If both input leads are shielded, connect the shield to the lower right terminal (marked ) which is at cabinet ground potential. If an input is ac, but a

23、t some dc level, the load on the Model 350C/D must also be floating, i.e. not con- nected to cabinet ground potential (+). 3-6. INPUT POWER LIMITATION. 3-7. Do not apply more than 5 watts maximumto the Model 350C/D INPUT terminals. For the Model 350C (input impedance, 500 ohms), 5 watts corresponds

24、to 2-1 3- 1 Section I C I Figure 3-1 Model 350C/D SOURCE r IN 5sv MODEL 350D ik4 I data for the Model 350D are given in figure 3-3 and table 3-3. The amount of insertion loss is included in tables 3-2 and 3-3. IMPEDANCE OF = 1. IMPEYNCE OF MODEL 350C = SOURCE OR LOAD ID-3-163 Figure 3-2. Model 350C

25、Matching Network Table 3-2. Model 350C Matching Network Values W lu (ohms) (ohms) Z (ohms) I I Insertion Loss 16 db 9 db 4 db 12 db 16 db 01307-1 3-3 Section 1 1 1 Paragraphs 3-15 to 3-16 z (ohms) 600 600 600 600 600 Model 350C/D Z U V W Insertion (ohms) (ohms) (ohms) (ohms) Loss 50 574.5 2.111 49.9

26、2 17 db 200 489.9 .9824 243.4 10 db 500 245.2 13.22 1148.0 4 db 2000 33.06 1674.0 670.8 11 db 5000 3.232 4690.0 636.2 15 db IMPEDANCE MODEL 350D OF - 0T4*w4-TA*2: SOURCE N OR C E LOAD OF sD-3-Ia. Figure 3-3. Model 350D Matching Network 3-15. NEED FOR OUTPUT MATCH. To maintain the rated attenuation a

27、ccuracy of the Model 350C/D, the impedance of the load must match the output impedance of the Model 350C/D. When the load also must be terminated in its matching impedance, a resistive matching network must be used. When mismatch does not affect the load, under some conditions the required impedance

28、 match for the Model 350C/D can be obtained by use of a single resistor. Conditions under which a resistor can be used, and use of matching networks, are discussed below. 3-16. MATCHING AT THE OUTPUT. a. When the impedance of the load is lower than that of the Model 350C/D and the load is not affect

29、ed by a mismatch, impedance match for the Model 350C/D output can be obtained by inserting a series resistor between 350C/D output and load. Resistor value should be the difference between the Model 350C/D output impedance and the load impedance. bo When the impedance of the load is much higher than

30、 that of the Model 350C/D, on the order of 50,000 ohms or more, impedance match for the Model 350C/D can be obtained by using -a shunting resistor across the Model 350C/D output. For the Model 350C, the shunting resistor shouldbe 500 ohms (see figure 3-1E), and for the Model 350D, 600 ohms. c. Netwo

31、rks may be used which provide the Model 350C/D and its load with an impedance match. Network data and connections are given in figures 3-2 and 3-3 and tables 3-2 and 3-3. Figure 3-1C shows a network for matching a 200-ohm load and the 600-ohm Model 350D; figure 3-1D shows a network for matching a 50

32、0-ohm load and the 600-ohm Model 350D. * 3-4 01307-1 I Model 350C/D Section V Paragraphs 4-1 to 4-8 SECTION IV PRINCIPLES OF OPERATION 4-1. GENERAL. 4-2. The Model 350C/D is shown in simplifiedsche- matic form in figure 4-1. In the complete schematic (figure 5-6) note that eachattenuator section, 10

33、 db and 100 db, is composed of four segments, each basically the same configuration as shown in figure 4-1. The attenuator circuit ground is isolated from the cabinet ground by capacitor C1, to allow a floating input, Le. an ac signal at a dc level. 4-3. ATTENUATION EXPRESSED IN DECIBELS. 4-4. POWER

34、 AND VOLTAGE RATIOS. 4-5. The basic equation for computing attenuation in decibels is based on a power ratio where P = power, V = voltage, and R = resistance: no. of decibels = 10 loglo 7 (2) V2 Since power is expressed as: P = - R The basic rules for exponents of logarithms then allow equation (4)

35、to be written as: no. of db = 20 loglo (%) (5) 4-6. The values of attenuation factor given in table 3-1 are based on a voltage ratio assuming the resist- ance at the input and output is the same. Values for Af are computed using equation (5) where V i = Vin and V2 = Vout: (6) 1 in Vout Vout = VinAf

36、or - =- Af Then substituting equation (6) in equation (5) gives (*) no. of db = 20 loglo Solving for Af gives (7) (8) 1 Equation (1) may be rewritten as: A = no. of db v1 antiloglO 20 An example will check the value for Af given in table no. of db = 10 loglo k) (3) 3-1 to 24 db. - (9) 1 - - 1 and if

37、 R1 = R2 then, no. of db = 10 loglo antiloglO ( 20 24) antiloglO (1.2) From a log table, the antiloglo of 1.2 is 15.85 and (4) A = (10) -= 0.0631 f 15.85 4-7. REFERENCE FOR DB. 4-8. The db levels given in figure 3-1 are referenced to a milliwatt of power, hence the term dbm. This indicates that the

38、logarithm is taken of a power ratio where 1 milliwatt is the reference. For the 37 dbm shown in figure 3-1E, equations (1) and (2) show that: I1 - 1 1 1 / 502 100 Q0 IO DB so-Y-116 ATTENUATOR ATTENUATOR * I 1 milliwatt dbm = lo loglo Figure 4-1. Model 350C/D Simplified Circuit dbm = 10 loglo (5000)

39、= 10 (3.7) = 37 01307-1 i Section V Figure 5-1 use care to avoid damage to cable insulation. This frees each attenuator for individual repair or replacement. g. Reassembly is essentially the reverse of the above procedure. 5-8. REPLACEMENT OF RESISTORS. 5-9. Figure 5-3 identifies the resistors on th

40、e 100 db attenuator, Al, and figure 5-4 on the 10 db atten- uator, A2. Replacement resistors may be ordered from the parts information in section VI. When a resistor is replaced, a padding resistor may be nec- essary to restore calibration accuracy. Contact your Engineering Representative or Custome

41、r Service for additional help or information. I 5-10. DC PERFORMANCE CHECK. 5-11. TEST EQUIPMENT. 5-12. A dc performance check of the Model 350C/D may be made without removing any of the instrument covers, using only external connections for the test equipment. Figure 5-5 shows a test setup using th

42、e equipment listed in table 5-1. Any substitute test equipment should provide the minimum required specifications in table 5-1. 5-13. TEST PROCEDURE. 5-14. The following procedure should be used for a dc performance check of the Model 350C/D: a. Connect test equipment as shown in figure 5-5. The inp

43、ut from the dc voltage source is connected to the top and the lower left of the Model 350C/D INPUT terminals. b. Set both Model 350C/D attenuator DB knobs to the “0” position. 5-1 Section V Figure 5-3 Model 350C/D FROM JI Y l TO R13 ON S 2 F I . . u 1 . m 6. YP-5-1100 TO R13 ON S2F t FROM J I I piFi

44、F1 I I R 8 R6 Figure 5-3. Assembly A1 Component Identification. 5 -2 01307-1 Model 350C/D Section V Figure 5-4 FROM R8 O N S I H TO 52 - 1 , / R I7 I R18 R 23 YP-s-1101 TO J2 FROM R 8 ON, SIH RI s2 i R16 R7 YP-S-11021 Figure 5-4. Assembly A2 Component Identification 01307-1 5-3 Section V Paragraphs

45、5-15 to 5-16 c. Adjust the output of the dc voltage source to 50 volts if checking a Model 350C or to 55 volts if check- ing a Model 350D. All voltage readings are as indicated by the voltage divider and potentiometer setup. Minimum Reading Model 350C/D Nominal Maximum Reading Reading d. Change the

46、10 DB attenuator in 1 db steps and compare the readings with those given in table 5-2 or 5-4. Return the 10 DB knob to the “0” setting. Attenuator Setting 10 20 30 40 50 60 80 90 100 m e. Change the 100 DB section in 10 db steps and compare the readings with those given in table 5-3 or 5-5. Minimum

47、Nominal I Maximum I Reading Reading 16.897 17.391 5.350 5.50 1.691 1.739 0.535 0.550 0.1691 0.1739 0.055 0.0535 ?I 169.lmv J23.9mv 5.19mv 5.5mv 519pv 550pv 1.64mv 1.74mv Table 5-2, Attenuator Setting 6 9 10 Model 350C 10 DB Attenuator Check With Input Set to 50 Volts Minimum Nominal Maximum Reading

48、Reading Reading 44.565 39.71 5v 35.390 31.550 28.115 25.060 22.335 19.905 17.740 15.810 Table 5-3. Model 350C 100 DB Attenuator Check With Input Set to 50 Volts I Attenuator I Minimum I Nominal I Maximum1 20 30 40 50 60 70 80 90 100 Reading Reading 15.367 15.810 4.863 5.000 1.537 1.581 ,4863 ,500 .1

49、537v .1581v .0486v .050v 15.37mv 15.8mv 4.72mv 5.0mv 1.49mv 1.58mv 472uv 500uv Reading 16.291 5.151 1.629 ,5151 .1629v .0515v 16.29mv 5.29mv I- 1.68mv Note: Do not use the 15 volts range or lower on the Leeds and Northrup Model 7592. These ranges will cause an impedance mismatch between the volt box and Model 3 50C/D, degrading the att