Segment Frequency Duration Level Target Reading
1. 5kHz 100ms +8dBu PPM6
2. 5kHz 10ms +8dBu PPM5½
3. 5kHz 5ms +8dBu PPM5
4. 5kHz 1.5ms +8dBu PPM3¾
5. 10kHz 0.5ms +8dBu PPM1¾
6. 1kHz 4s +12dBu PPM7
1kHz 4s +8dBu PPM6
1kHz 4s +4dBu PPM5
1kHz 4s 0dBu PPM4
1kHz 4s -4dBu PPM3
1kHz 4s -8dBu PPM2
1kHz 4s -12dBu PPM1
Note that the PPM test sequence 18 does not output any FSK and therefore only runs once
(even if both channels, L+R are selected). Other meters can also be tested by
programming the suitable tone bursts (see section 4.16).
3.16 Normalisation of Frequency Response Graph normalisation 400Hz normalisation
Frequency response graphs are usually normalised to 1kHz initially (ie the 1kHz level is
set as a test level) with each channel being normalised independently to its own 1kHz
level. However, other frequencies can be used for normalisation by setting configuration
J1 for 315Hz, J2 for 400Hz or J3 for 1kHz. Alternatively, absolute results (in dBu) can be
displayed by setting configuration J0.
TL on frequency response graph absolute level Test level on frequency response graph
This default normalisation can be overridden when the graph is displayed by pressing
to turn test level on and off. The letters ‘TL’ indicate that the displayed level is
relative to a test level (similar to the test level facility in manual mode), and initially the
test level will be set so as to normalise the frequency response results to a frequency
determined by configuration J (as described above). Pressing
when ‘TL’ is
displayed will turn the test level off causing the frequency response results to be shown as
absolute levels (in dBu). Pressing
again will set the test level to the displayed
cursor level, normalising the results to the frequency at the cursor; so positioning the
cursor at 100Hz and operating
twice will leave a graph normalised to 100Hz
(leaving the graph display resets the test level to its default). Printed graphs are not
affected by the test level setting as they always use the normalisation determined by
configuration J.
Normalisation operates independently on each channel, so it is quite possible to normalise
the left channel to 315Hz (using the
facility) while leaving the right channel
normalised to 1kHz. The difference graph is calculated from the normalised level on the
right channel minus the normalised level on the left channel, but it is also possible to set a
third, independent test level on the difference graph.
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3. Sequence Testing
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