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Service Procedures Product: CFG253 3 Mhz Function Generator Title: Performance Verification & Adjustment Procedure #: CP1005 Revision: A Prepared By: Roy Lindley Measurement Business Service Support REVISION LEVEL SUMMARY: Revision # Date Initiator Level Change Description From: 5/16/97 Roy Lindley...
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CFG253 PERFORMANCE VERIFICATION PROCEDURE CONTENTS: Preparation Check DC Offset Check Main Output Amplitudes Square Wave Overshoot, Rise/Fall Time Check Square Wave Duty Cycle Sync (TTL) Output Sine Wave Distortion Frequency Dial Accuracy INTRODUCTION To ensure instrument accuracy, check its performance after every 2000 hours of operation or once each year if used infrequently.
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PREPARATION Connect the instrument and test equipment to an appropriate power source and allow 20 minutes for warm up and stabilization. Set the controls as listed below during warm up. Initial CFG253 Set-Up: AMPLITUDE Mid Range DC OFFSET Pushed In...
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Set the test scope Volts/Div to 0.2 V. Rotate the AMPLITUDE knob fully CW. Check the display for > 5 divisions (1V). Return the VOLTS OUT button to the out position and ensure that the AMPLITUDE is CW. CFG253 Performance Verification & Adjustment Procedures Page 4 of 19 Procedure #: CP1005 Revision: A...
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Set the FUNCTION to Square Wave. Use the CFG253 and test scope settings in Table 1 to check the MAIN OUTPUT AMPLITUDE for the indicated settings : TABLE 1 Function Range Volts Out Freq. Test Scope Test Scope button Dial...
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Set test scope Trig Slope to - (negative). Adjust Trig Level to view the Falling edge of Square Wave. Check the Fall Time between the 10% and 90% points for < 100 nSec (2 Div). CFG253 Performance Verification & Adjustment Procedures Page 6 of 19...
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CW and check for the same half cycle to increase to 5 divisions or greater (a duty cycle change of 5:1). Return the SYMMETRY knob to the center detent position and the test scope Time/Div variable to the detent position. CFG253 Performance Verification & Adjustment Procedures Page 7 of 19 Procedure #: CP1005 Revision: A...
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(without the 50 ohm terminator). Check the test scope for a display of approximately 4 volts (4 divisions). Repeat step d with the FUNCTION set to Square Wave and Sine Wave. CFG253 Performance Verification & Adjustment Procedures Page 8 of 19...
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< 1 % < 1 % < 1 % FREQUENCY DIAL ACCURACY Set-Up: AMPLITUDE RANGE FUNCTION Triangle VOLTS OUT Button In FREQ/10 Button Out FREQ DIAL CFG253 Performance Verification & Adjustment Procedures Page 9 of 19 Procedure #: CP1005 Revision: A...
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Connect the CFG253 MAIN OUTPUT to the input of a Frequency Counter. Check the frequency reading for each set-up listed in Table 6: Table 6 RANGE FREQ DIAL COUNTER READING 2.85 MHz - 3.15 MHz 150 KHz - 450 KHz *...
It is necessary to remove the bottom cover from the instrument to gain access to the adjustments used in this procedure. Turn off the POWER switch, disconnect the power cord and place the CFG253 upside down on its top. Remove the 2 screws in the rear feet and the 2 screws BESIDE the front feet.
All test equipment is assumed to be operating within tolerance. Detailed operating instructions for test equipment are not given in this procedure. If operating information is needed, refer to the appropriate test equipment instruction manual. Initial CFG253 Set-Up: AMPLITUDE DC OFFSET Pushed In...
Set test scope Vert Coupling to GROUND, center the trace, then set Coupling back to DC. Slowly adjust R82 to recenter the trace, set to within 1 division of center (+/- 10 mV). CFG253 Performance Verification & Adjustment Procedures Page 14 of 19 Procedure #: CP1005 Revision: A...
Check the Fall Time between the 10% and 90% points for < 100 nSec (2 Div). Set OUTPUT Levels Set-Up: AMPLITUDE DC OFFSET Pushed In RANGE FUNCTION Triangle VOLTS OUT Button Out FREQ/10 Button Out FREQ DIAL CFG253 Performance Verification & Adjustment Procedures Page 15 of 19 Procedure #: CP1005 Revision: A...
VOLTS OUT Button Out FREQ/10 Button Out FREQ DIAL Connect the MAIN OUTPUT to the Distortion Analyzer via a coax cable and a 50 ohm terminator. CFG253 Performance Verification & Adjustment Procedures Page 16 of 19 Procedure #: CP1005 Revision: A...
If a Frequency Counter is not a available, see alternate procedure on next page. Adjust R6 for a reading of 3.0 KHz on the Frequency Counter. CFG253 Performance Verification & Adjustment Procedures Page 17 of 19 Procedure #: CP1005 Revision: A...
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Set the RANGE to 1M and adjust C8 for a reading of 3.0 MHz on the Frequency Counter. Check the Frequency Counter readout while changing the CFG253 FUNCTION between Sine Wave and Square Wave. Adjust R76 for approximately 3.0 MHz, setting for the best compromise between Sine Wave and Square Wave.
REASSEMBLY Disconnect any cables connected to the CFG253, turn off the POWER switch and remove the power cord. With the unit setting upside down on its top, place the handle upside down in its opening in the case top and carefully slide the case bottom onto the unit. Be sure that the front and back grooves line up and slip over the front and rear panels.
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