HP-460BR-Manual 电路图.pdf

HP Archive This vintage Hewlett Packard document was preserved and distributed by vvwvv. h parc Please visit us on the web ! Scanned by on-line curator: Tony Gerbic * For FREE Distribution Only * RadioFans.CN 收音机爱 好者资料库 460BR FAST PULSE AMPLIFIER OPERATING AND SERVICING MANUAL RadioFans.CN 收音机爱 好者资料库 O P E R A T I N G AND SERVICING MANUAL F O R MODEL 46OBR FAST PULSE AMPLIFIER Serial 1720 and Above 5 r J HE WLETT -PACURD COMPANY 275 PAGE MILL ROAD, PAL0 ALTO, CALIFORNIA, U. S. A. 46 OB 004-3 RadioFans.CN 收音机爱 好者资料库 SPECIFICATIONS Frequency Res pons e : Gain: Output Impedance: Rated Output: Maximum Output: Input Impedance: Noise Figure: Delay Characteristics: Rise Time: Power Supply: Size: High Frequency - closely matches Gaussian curve when operating into a 200-ohm resis- tive load. 3 db point is 120 mc. Low Frequency - off approx. 3 db at 100 kc when operating into a matched load. Off ap- prox. 3 db at 3 kc when operating into an open circuit (i. e., CRT plates) or succeed- ing amplifier. With 410B VTVM - when used with 46A-95D Adapter, response +1 db, 200 kc to 200 mc. Approximately 15 db into 200 ohm load. Approximately 200 ohms. Linear Amplifier - Approximately 8 volts peak into a 200 ohm load or 16 volts peak into open circuit. Pulse Amplifier - Approximately 125 volts negative peak open circuit (unilateral) pulse operation 10% duty cycle. 200 ohms (t8 volts input required for 125 volts output). Less than 6 db. Approximately . 016 psec. Approximately 0.003 psec. No appreciable overs hoot. 19 relay rack panel, 5-1/4 high; 6-3/4deep. Weight: 12 lbs. Shipping weight 18 lbs. Accessories Available: Y W a v a 5 a a 460 B LINEAR PEAK VOLTS INPUT 460 B 4608 LINEAR PULSE Figure 3 . Linearity Characteristics of 460BR Amplifier .25 V 2 .H .25V 460 A _I 460 B PULSE 460A 1 - .25V 2.5V 460 8 LINEAR 460 A i Figure 4. Cascading 460 Amplifiers 460 B PULSE with an appropriate receptacle. to connect this plug to a standard two contact system. the adapter is used, the ground connection is brought out on a short wire. This ground lead should then be connected to a suitable ground for the protection of operating personnel. An adapter may be used When INPUT AND OUTPUT The input and output jacks on the control panel, require special 200-ohm connectors and cables. (See paragraph 1-2). 2 -4 OPERATION Connect the Model 460B to the power line, turn on the power switch and the instrument is in operation. To use as a linear amplifier to amplify sine waves, etc. , or pulses of either polarity, set the LINEAR-PULSE switch to the LINEAR position. position the output is limited to 16 volts peak into an open circuit or 8 volts peak into a 200-ohm load. a phase reversal between input and output is present and that a positive input pulse appears in the output as a negative pulse. When the LINEAR-PULSE switch is in this It must be remembered that To realize the full output capabilities of the Model 46OB, the LINEAR-PULSE switch must be in the PULSE position and a posi- tive pulse of about 8 volts peak be supplied to the input. In the PULSE position of the LINEAR-PULSE switch the amplifier tubes are operated at higher than normal supply voltages. grid bias is increased to keep tube dissipation within ratings. Under these conditions (1-8 volt input) the rated tube dissipation is reached with a duty cycle of 10%. Lower driving voltages will allow proportionally higher duty cycles, but the output voltage will be lower. The See Figure 3. In order to supply this 8-volt positive pulse to a Model 460B, the units may be cascaded or used with one or more Model 46OA Wide Band Amplifiers, see Figure 4. In general, when cascading 460 amplifiers, consideration must be given to the polarity as well as the amplitude of the pulse to be amplified. For maximum deflection, the set-up must be arranged so that the input to the last 460BR amplifier is positive and of approximately 8 volts peak amplitude. This is easily done because the 460BR inverts the in- put pulse. Hence, an additional 460B can be used when necessary to invert pulse polarity. In most applications an input of about 4 volts is sufficient to give satisfactory deflection of a cathode-ray tube. Certain precautions must be taken when cascading several 460 Amplifiers, see Paragraph 2-2, INSTALLATION. -5- SECTION 1 1 1 THEORY OF OPERATION 3-1 DISTRIBUTED AMPLIFIER The extremely rapid rise time of the 460B is obtained through the use of the distributed amplifier;* the operation of which is explained as followsa See Figure 5. In the distributed amplifier, the tubes are connected at fixed inter- vals between two artificial transmission lines that have equal pro- pagation velocities. A signal applied to the input terminals passes down the grid line and appears on each grid in turn. The resulting plate signal currents flow in the plate line, half in one direction and half in the other. tube to the output are the same length in terms of line sections traversed, the individual plate signal currents will arrive at the output termination in phase, thus adding together in the load. The plate signal currents flowing in the reverse direction are absorbed without reflection in the reverse plate line termination. put voltage of a distributed amplifier is given by the relation Eo - plate signal current, and Zp is the plate line impedance. Since the paths from the input through any The out- - nZp - r i p where n is the number of tubes in the stage, ip is the The number of tubes that can be used in a single stage is limited by grid loading which occurs at high frequencies because of the increased input conductance of the amplifier tubes. This effect reduces the high frequency gain and in effect restricts the fre- quency range of the amplifier. When amplifiers are cascaded, the rise time will be greater than that of a single unit in accordance with the relation: T = 112 where: T is total rise time t is the rise time of a single n is the number of 460 units. unit (2mbXlO-9 sec.) In addition to the rise time of the amplifiers, the rise time of the RC combination formed by the capacitance of the deflection gates * Ginzton, Hewlett, et all, Distributed Amplification, Proc. IRE, Vola 36, August, 1948 and the internal resistance of the 460B (200 ohms) shouldbe consider e d. In any case, the total rise time of any number of 460 Amplifiers in conjunction with any load may be found approximately by the following relation: where: n = number of 460 Amplifiers t rise time of one 460 = 2.6XlO-9 sec. C T total rise time. total shunt capacitance on the output of the 460 in farads. -8- SECTION IV MAINTENANCE 4-1 4-2 4-3 COVER REMOVAL You will be able to slide the one-piece cover off the instrument after removing the four screws in the rear of the cover. TUBE REPLACEMENTS In many cases instrument malfunction can be corrected by replac- ing a weak or defective tube. ment or component replacement, check the tubes. Adjustments made in an attempt to compensate for a defective tube will often complicate the repair problem. Before making any internal adjust- It is good practice to check tubes by substitution rather than by the use of a tube checkert1. The results obtained from the tube checker can be misleading. Mark original tubes to insure re- turn to the same socket. defective Replace only tubes proved to be weak or Any tube with corresponding standard E E I A (JEDEC) characteristics can be used as a replacement. POWER SUPPLY The 460B power supply delivers two output voltages depending upon the setting of PULSE-LINEAR switch S1. With S1 in the PULSE position, selenium rectifiers CR-1 and CR-2 are connected in a voltage doubler circuit. The dc output voltage between ground and the common junction of capacitor C22, filter choke L28, and fuse F2 with the line voltage set to 115 volts will be 270 -hp- Stock No. 18-109, Mfr., CC Change to lamp, incandescent, 6-8V, 2 pin base, GE #12; -hp- Stock No. 211-78, M f r . , I 7 Change t o power cord; -hp- Stock No. 812-106, Wr., TT Dele te Change to lampholder -hp- Stock No. 145-25, M f r . , HP Change jewel, pilot lamp, to -hp- Stock No. 145-23A, M f r . , HP For instruments with Serials Prefixed: 0030, the manual for Serial 1720 and above applies with a l l corrections l i s t e d above. For instruments with Serials Prefixed: 041-, include the following changes in addition to those previously listed: C5,19: Change to capacitor, fixed, ceramic, .Oluf 2 2 V % 9 , 100 vdcw; -hp- Stock NO. 0150-0098, Mfr., RAE c20 : Change to capacitor: fixed, ceramic, .OTuf 22076, 400 vdcw; -hp- Shock No. 15-161, Mfr., NN 10/18/60 - 46OBR 3/3/60 1/12/60