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made on preprinted amplitude/frequency calibrated paper:- QP 0123 -
0423- 1123.
The mechanical connection between the Level Recorder and Oscillator is
obtained with a permanent chain drive which may be connected either to
DRIVESHAFT 1 or 2, the latter giving the possibility of varying the relative
speed between the paper drive and the chain drive for compression and
expansion of the recorded curves. Connection of the two driveshaft is further
described in the instruction book for the Level Recorder Type 2305.
Automatic Frequency Response Recorder Type 3328.
The Automatic Frequency Response Recorder Type 3328 has been developed
to allow continuous recording of the frequency response of electrical, electro-
acoustic or electromechanical networks in the range 2 Hz to 200ooo Hz.
The B
&
K combination mounting unit consists of the two Beat Frequency
Oscillator Type 1013 and 1017 and the Level Recorder Type 2305.
To allow automatic operation over the full 5 frequency decades 2-200ooo Hz,
two built-in relays ensure proper cross-over from the use of the one oscillator
to the use of the other.
Note. All terminal connections should be made to the Type 1013 oscillator.
The only "critical" part of the operation is the adjustment of the output and
compressor control potentiometer. The setting of these potentiometers must
be made separately on each oscillator and in such a way that the same
amount of compression takes place on both sides of the cross-over fre-
quency.
The cross-over frequency is adjusted at the factory to be 2ooo Hz but can
be adjusted to any frequency (between 200 and 2ooo Hz) if desired.
Three push-buttons on the front of the combination unit allow proper
selection of operation. When the push button marked "1017" is pressed the
output from the 1017 will be available on the output terminals of the Type
1013 oscillator. The compressor of the 1017 is now controlled by the signal
applied to the COMPRESSOR INPUT of Type 1013. The BFO Type 1013 is
in this case set out of operation by means of the built-in relay -
circuits.
Pushing the button marked "1013" the Type 1013 oscillator is in operation
while the 1017 oscillator is disconnected.
If
the push-button marked AUTO is pressed the 1017 oscillator is in operation
below the cross-over frequency while the 1013 oscillator is in operation above
the cross-over frequency.
Two lamps placed beside the push-buttons indicates which instrument is
actually in operation.
Finally, it is also possible to operate the two oscillators separately dis-
connecting the interconnecting cable and inserting the shorting plugs,
supplied with the instruments upon delivery.
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