BK 1471 Instruction Manual 电路图.pdf

!47 1 D u al -T r ace Osc I I I osco p A Product of DYNASCAN CORP0RATI0N 1801 West Belle Plaine . Chicago, lllinois 60613 10 MHz, TRIGGERED SWEEP v v PRTCE $2.00 RadioFans.CN 收音机爱 好者资料库 lv b INSTRUCTION MANUAL FOR B brightness increases in logic low state, decreases in logic high state. v , SPECIFICATIONS v VERTICAL AMPLIFIERS (CH A aNd CH B)TV SyncVertical and horizontal sync separator circuit provided so that any portion of complex TV wave- form can be synchronized and expanded for viewing. TVH (line) and TW (frame) sync switched automatically by SWEEP TIME/ CM switch. TW = 0.5 SEC/cm to 0.1 mSEC/cm. TVH = 50 pSEC/cm to I pSEC/cm. HORIZONTAL AMPLIFIER (Horizontal Input through CH B Input) Deflection Factor .01 V/cm to 20 V/cm. Frequency Response DC to 800 kHz e3 dB). Input Resistance I megohm (nominal). Input Capacity 22 pF (t 3 pF). Madmum Input 300 V (ttC + AC peak) or 600 V Voltage p-p. X-Y Operation With SWEEP TIME/CM switch in CH B position, the CH A input becomes the Y input (vertical) and the CH B input becomes the X input (horizontal). The CH B posi- tion control becomes the horizon- tal position control. CALIBRATION VOLTAGE I V p-p square wave (+ 5%) atline frequency. INTENSITY MODULATION VoltageTTL logic-compatible. Low logic - increases brightness; high logic decreases brightness. lnput Resistance 470 kCl (nominal). POWER REQUIREMENTS Input ll7 or 230 VAC, I lVo,5016O Ifz, 20 watts. (3-wire line cord, CSA-approved for oscilloscopes.) See Fig. 51. PROBES (Not Included) b Deflection Factor Calibration Accuracy Frequency Response Risetime Overshoot Ringing Input Resistance Input Capacity Max. Input Voltage Operating Modes Chop Frequency Channel Separation Sweep System Sweep Time Sweep Time Accuracy Sweep Magnification Horizontal Linearity TRIGGERING Source Slope Triggering Range 0.01 V/cm to 2O Y lcm in I 1 calibrate d range s in l-2-5 sequence. ! 5% on all ranges. DC: DC to 10 MHz (- 3 dB) AC: 10 Hzto l0 MHz e3 dB). 35 nanoseconds. 3% or less at 100 kHz squarewave display. 3% or less at 100 kHz squarewave display. I megohm, + 5%. 22 pF (t 3 pF). 300 V (DC + AC peak) or 600 V p-p. Channel A only. Channel B only. Dual-trace automatically chopped at all sweep times of I mS/cm and slower; alternate trace automati- cally selected for all faster sweep times. 2OO kHz (x 2Wo). Better than 60 dB I kHz. Triggered and automatic. In auto- matic mode, sweep is obtained without input signal. I pSEC/cm to 0.5 SEC/cm in 18 calibrated ranges, in l-2-5 se- quence. ! 5%. Obtained by enlarging the above sweep 5 times from center. Maxi mum sweep speed becomes O.2 pSEC/cm. 3Vo or less distortion. I N T a n d E X T ( l V p - p sensitivity). MODE switch selects source of internal trigger; the CH A signal is the triggering source in the CH A and DUAL modes, and the CH B signal is the triggering source in the CH B mode. Positive and negative, continuous- ly variable level control; pull for AUTO. 20 Hz to l0 MHz (rrrih. I cm deflection as measured on cathode ray tube). Model No. Attenuation lnput Impedances Connector Tip PR-208 or PR-24B. Combination l0: I and direct. l0:1 = l0 megohms, l8 pF. Direct = I megohm, 120 pF. BNC SpringJoaded, hook-on tip. SWEEP CIRCUITS (Common to CH A and CH B) v 6 7 8 10 15171819 Fig. 1. Front panel controls and indicators. OPERATORS CONTROLS. INDICATORS AND FACILITIES v l . Cathode Ray Tube (CRT). This is the screen on which the waveforms are viewed. Scale. The 8 x l0 cm graticule provides calibration marks for voltage (vertical) and time (horizontal) measurements. Pilot Lamp. Lights when oscilloscope is turned on. SWEEP TIME/CM Switch. Horizontal sweep time selector. Selects calibrated sweep times of 1 pSECicm (microsecond per centimeter) to 0.5 SEC/cm in l8 steps. In the CH B position, this switch disables the internal sweep generator and permits the CH B input to provide horizontal sweep. CAL I V P-P Jack. Provides calibrated I volt peak-to- peak square wave input signal at the line frequency. This is used for calibration of the vertical amplifier attenuators. POSITION Control. Rotation adjusts horizontal position of traces (both traces when operated in the dual trace mode). Push-pull switch selects 5X magnifi- cation when pulled out (PULL 5X MAG): normal when pushed in. TRIGGERING LEVEL Control. Sync level adjustment determines points on waveform slope where sweep starts; (-) equals most negative point of triggering and (+) equals most positive point of triggering. Push-pull switch selects automatic triggering when pulled out (PULL AUTO). When automatic triggering, a sweep is generated even without an input signal. EXT TRIG Jack. Input terminals for external trigger signal. SYNC Switch. Four-position lever switch with the following positions. SLOPE. The SLOPE positions are used for viewing all waveforms except television composite video signals. (+) Sweep is triggered on positive-going waveform. (-) Sweep is triggered on negative-going waveform. slope of slope of TV. In the TV positions, the sync pulses of a television composite video signal are used to trigger the sweep; the vertical sync pulses (frame) are automatically selected for sweep times of 0.5 SEC/cm to 0.1 mSEC/cm, and horizontal sync pulses (line) are automatically selected for sweep times of 50 pSEC/cm to I pSEC/cm. (+) Sweep is triggered on positive-going sync pulse. (-) Sweep is triggered on negative-going sync pulse. SOURCE Switch. Selects triggering source for the sweep. INT Sweep is triggered by CH A signal when MODE switch is in CH A or DUAL position. Sweep is triggered by Channel B signal when MODE switch is in CH B position EXT Sweep is triggered by an external signal applied at the EXT TRIG jack 8. I l. Channel B POSITION Control. Vertical position adjust- ment for Channel B trace. Becomes horizontal position adjustment when SWEEP TIME/CM switch 4 is in the CH B position. 12. Channel B DC BAL Adjustment. Vertical DC Balance adjustment for Channel B trace. 13. Channel B INPUT Jack. Vertical input jack of Channel B. Jack becomes external horizontal input when SWEEP TIME/CM switch 4 is in the CH B position. 14. Channel B DC-GND-AC Switch. DC Direct input of AC and DC component of input signal. GND Opens signal path and grounds input to vertical amplifier. This provides a zero-signal base line, the position of which can be used as a reference when performing DC measurements. AC Blocks DC component of input signal. 15. Channel B. VOLTS/CM Switch. Vertical attenuator for Channel B. Vertical sensitivity is calibrated in 1l steps from .01 to 20 volts per cm. This control adjusts horizontal sensitivity when the SWEEP TIME/CM switch 4 is in the CH B position. 16. MODE Switch. Three-position lever switch; selects the basic operating modes of the oscilloscope. CH A Only the input signal to Channel A is dis- played as a single trace. CH B Only the input signal to Channel B is dis- played as a single trace. DUAL Dual-trace operation; both the Channel A and Channel B input signals are displayed on two separate traces. 17. Channel A VOLTS/CM Switch. Vertical attenuator for Channel A. Vertical sensitivity is calibrated in 1l steps, from .01 to 20 volts per cm. 18. Channel A DC-GND-AC Switch. DC Direct input of AC and DC component of input signal. GND Opens signal path and grounds input to vertical amplifier. This provides a zero-signal base line, the position of which can be used as a reference when performing DC measurements. AC Blocks DC component of input signal. 19. Channel A INPUT Jack. Vertical input jack of Channel A. 20. Channel A DC BAL Adjustment. Vertical DC balance adjustment for Channel A trace. 21. Channel A POSITION Control. Vertical position ad- justment for Channel A trace. 22. FOCUS Control. 23. POWER/INTENSITY Control. Fully counterclockwise rotation of this control (OFF position) turns off oscilloscope. Clockwise rotation turns on oscilloscope. Further clockwise rotation increases brightness of the trace. 1 3. 4. 5. 6. 7. v 8. 9. 10. v 24. INT MOD Jack.Intensity modulation (Z-axis) input. probe designed for use with an oscilloscope hav 25. AC Line Cord (See Fig. 2). CSA-approved for oscil- nominal input impedance of I megohm shunte loscopes. tu s!w 6 2 ven-ar,PrvYvu rvr J5 pF and capable of operation up to 10MHz, c 26 Pro.bi*9-Fie 3-) The B lN THIS CASE ALIGN WHEREVER WAVEFORM BEGINS. o 3 f r f POSITION CONTROL ADJUSTED SO THAT TRAILING EDGE OF WAVEFORM CROSSES HORIZONTAL SCALE MARKER FOR ACCURACY AND EASE OF READING EXAMPLE: HORIZONTAL DEFLECTION = 6.35cm SWEEP TIME/CM = 10pSEC TIME DURATION = 63.5pSEC (or PERIOD) OF WAVEFORM FREOUENCY = 1 TrME .0000635 SEC DISPLAYS SHOW TYPICAL TELEV!SION RECEIVER WAVEFORM AT GRID OF HORIZONTAL OUTPUT TUBE = 15,750 Hz v Fig. 5. Typical time measurement. horizontal deflection (in cm) by the SWEEP TIME/CM switch 4 setting (see example in Fig. 5). Remember, when the 5X magnification is used, the result must be divided by 5 to obtain the actual time duration. 6. Time measurements often require external sync. This is especially true when measuring delays. The sweep is started by a sync signal from one circuit and the waveform measured in a subsequent circuit. This allows measurement of the display between the sync pulse and the subsequent waveform. To perform such meas- urements using external sync, use the following steps: a. Set the SOURCE switch l0 to the EXT position. b. Connect a cable from the EXT TRIG jack 8 to the source of sync signal. Use a short shielded cable. c. Set the SYNC switch 9 to the SLOPE (+) or (-) position for the proper polarity for the sync signal. d. Readjust the TRIGGERING LEVEL control 7 if necessary for a stable waveform. e. If measuring a delay, measure the time from the start of the sweep to the start of the waveform. 7. Another excellent method for measuring time delays is with dual-trace operation. The procedures are given in the DUAL-TRACE APPLICATIONS section of the manual. EXTERNAL HORTZONTAL rNPUT (X-y OPERATTON) For some measurements. an external horizontal deflec- tion signal is required. This is also referred to as an X-Y measurement, where the Y input provides vertical deflec- tion and the X input provides horizontal deflection. The horizontal input may be a sinusoidal wave, such as for phase measurement, or an external sweep voltage. This input must be l0 mV per cm of deflection or greater;thus any voltage of 100 mV or greater is sufficient for satisfactory operation. To use an external horizontal input, use the following procedure: 1. Set the SWEEP TIME/CM switch 4 fully clockwise to the CH B position. 2. Use the Channel A probe for the vertical input and the Channel B probe for the horizontal input. 3. Adjust the amount of horizontal deflection with the CH B VOLTS/CM control 15. 4. The CH B POSITION control I I now serves as the horizontal position control, and the POSITION control is disabled. NOTE Do NOT use the PULL 5X MAG control during X-Y operation. Use the CH B VOLTS/CM control to adjust horizontal gain. 5. All sync controls are disconnected and have no effect. Z.AKS INPUT The trace displayed on the screen may be intensity modulated (Z-axis input) where frequency or time-scale marks are required. A TTL compatible signal applied at the INT MOD (intensity modulation) jack 24 on the rear of the oscilloscope will provide alternate brightness and blanking of the trace. See Fie. 6. r2 Fig. 6. Oscilloscope trace with Z-axis input. DUALTRACE WAVEFORM OBSERVATION (Refer to Fig. 7) In observing simultaneous waveforms on channels A and B, it is necessary that the waveforms be related in frequency or that one of the waveforms be synchronizedto the other although the basic frequencies may be different. An example of this is in checking a frequency divider or multiplier. The reference, or clock frequency can be used on Channel A, for example, and the multiple or submultiple of this reference frequency will be displayed on Channel B. In this way, when the waveform display of Channel A is eynchronized, the display on Channel B will also be in sync with the Channel A display. If two waveforms having no phase or frequency relationship to each other are displayed simultaneously, it will be difficult if not impossible to lock both waveforms in sync for any useful observation. To display two waveforms simultaneously for observa- tion, use the following procedure: l. Perform the steps of the Initial Starting Procedure. 2. Connect oscilloscope probe cables to both the CH A and CH B INPUT jacks 19 and 13. 3. If the recommended B ,iit|5hfr C H A A. REFERENCE FREOUENCY PULSE TRAIN (1OOO PULSES PER SECOND) LEADING EDGES MAY NOT BE VISIBLE AT FAST SWEEP RATES C H B B. DIVIDE . BY .TWO OUTPUT SYNCHRONIZED TO LEADING EDGE OF REFERENCE PULSE . l*to c H B l C. DIVIDE .BY .TWO OUTPUT SYNCHBONIZED TO TRAILING EDGE OF REFERENCE PULSE WAVEFORM A H E I G H T l mS/cm WAVEFORM B WAVEFORM A WAVEFORM B H E I G H T v Fig. 7. Waveforms in divide-by-two circuit. l3 to those previously described for single-trace operation. Either the Channel A or Channel B vertical adjustment controls can be used as required in conjunction with the horizontal sweep controls to obtain the required amplitude or time interval measurements. This can be done either by using the dual display facilities such as the DUAL position of the MODE switch or by reverting to single-trace operation, using the CH A or CH B positions of the MODE switch. DU AL-TRACE APP LICATION S INTRODUCTION The most obvious and yet the most useful feature of the dual-trace oscilloscope is that it has the capability for viewing simultaneously two waveforms that are frequency- or phase-related, or that have a common synchronizing voltage, such as in digital circuitry. Simultaneous viewing of Cause and Effect waveforms is an invaluable aid to the circuit designer or the repairman. Several possible applica- tions of the dual-trace oscilloscope will be reviewed in detail to familiaize the user further in the basic operation of this oscilloscope. FREQUENCY DIVIDER WAVEFORMS Fig. 7 illustrates the waveforms involved in- a basic divide-by-two circuit. Fig. A indicates the reference or clock pulse train. Fig. B and Fig. C indicate the possible outputs of the divide-by-two circuitry. Fig.7 also indicates the settings of specific oscilloscope controls for viewing these waveforms. In addition to these basic control settings, the TRIGGERING LEVEL control, as well as the Channel A and Channel B vertical position controls should be set as required to produce suitable displays. In the drawing of Fig. 7 , the waveform levels of 2 cm are indicated. The Channel B waveform may be either that indicated in Fig. 7B or 7C. In Fig. 7C the divide-by-two output waveform is shown for the case where the output circuitry responds to a negative- going waveform. In this case, the output waveform is shifted with respect to the leading edge of the reference frequency pulse by a time interval corresponding to the pulse width. r N