BRUEL & KJAER 1617 - Page 24

is given with reference to the use of the 2307 with a 50 dB Range Potentiometer. For
use with a 25 or 75 dB Range Potentiometer a similar procedure may be used.
1. Connect the Band Pass Filter, Measuring Amplifier and Level Recorder as shown in
Fig.4.3.
2. Fit the Level Recorder with a 50dB Range Potentiometer, plus pen and roll of fre-
quency graduated recording paper QP 1143 or QP 1153.
3. Set Level Recorder controls:
POTENTIOMETER RANGE
RECTIFIER RESPONSE
LOWER LIMITING FREQUENCY
WRITING SPEED
PAPER DRIVE FUNCTION
PAPER SPEED
POWER
"50dB"
"DC" for DC recording, "RMS" for AC recording
depending on Measuring Amplifier output.
"200 Hz" for DC recording. Less than or equal to
start frequency of analysis for AC recording.
For effective averaging time in accordance with
start frequency of analysis. See section 5.3.1
"Continuous F"
"10 mm/s". Note for filter shift pulses the PAPER
SPEED slider switch must be set to "mm/s"
"On"
4. Calibrate the Measuring Amplifier and Band Pass Filter combination as described in
items 1 to 4 of section 3.2.
5. Keeping the internal or external reference source used for calibration connected,
turn the INPUT SECTION ATTENUATOR knob of the Measuring Amplifier one step
anticlockwise and adjust the GAIN CONTROL knob to obtain full scale pointer deflec-
tion on the indicating meter.
6. Keeping the reference source connected, adjust the INPUT ATTENUATOR and INPUT
POTENTIOMETER of the Level Recorder to move the pen to the thick line (50dB) at
the top of the recording chart.
The Level Recorder is now calibrated so that full scale pen deflection corresponds ex-
actly with full scale pointer deflection on the Measuring Amplifier, whatever meas-
urement range is selected. Avoid touching the INPUT POTENTIOMETER AND INPUT
ATTENUATOR of the Level Recorder of calibration will be lost.
7. Disconnect the reference source and set Band Pass Filter controls:
SELECTIVITY
RANGE
FILTER CONTROL MODE
MANUAL FILTER SELECTOR
"Bandwidth" and "Record Step" as required
"2 Hz - 20 kHz - A - Lin"
"Recorder"
To centre frequency of octave or third octave band
in which analysis is to commence.
8. To commence synchronization of the chart position with the filter switching of the
Band Pass Filter, turn the PAPER ADJUSTMENT and AUTOMATIC STOP wheels of
the Level Recorder so that the white spots marked on the wheels coincide and ap-
pear near the top of the opening on the front of the Recorder.
9. Momentarily press the PAPER DRIVE "Start" button on the Level Recorder and wait
until the paper drive stops automatically.
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