provide an indication of 400 microamperes on the left mag- 

 netic tape recorder meter. 



m) Move the polarity-reversing switch on the calibrate unit 

 to its other position. The strip-chart recorder pen should 

 indicate full scale on the other side of the chart paper, 

 and the magnetic tape recorder signal meter should indicate 

 400 microamperes on the opposite side of zero from that 

 found in 1) above. 



n) Readjust the bias meter signal to 0.8 volt. When switching 

 from "operate" to "calibrate", the bias meter will change 

 slightly; this is normal, and will not affect recorder 

 operation. 



o) The magnetic tape recorder is now calibrated for full-scale 

 recording of the signal that produces full-scale movement 

 of the strip-chart recorder pen. Since the strip-chart 

 recorder pen indicates the maximum wave height produced 

 by the wave gage, the magnetic tape recorder is also so 

 calibrated. 



Since all strip-chart recorders do not have the same sensitivity, 

 the wave-gage circuitry is adjusted to overcome this deficiency when the 

 wave gage is calibrated. Therefore, the calibration of the magnetic tape 

 recorder must be mated with the calibration of the strip-chart recorder 

 with which it operates. 



100 



