Rohde & Schwarz SR8000 Series, System Manual

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Chapter 5 Operation
5300.9677.71 - 5.60 - EN-4
2.7.6.1 Static Delay Function Applications
The Static Delay function can be applied for example in transmitter networks where trans-
mitters radiate the same program at different frequencies. If the signal is fed to the individual
transmitters in different ways, for instance via microwave link to one transmitter and via sat-
ellite to another, there will be a noticeable time difference in the program on switching over
between these two transmitters. This effect can be kept to a minimum in the "faster" trans-
mitter by controlling the delay with the aid of the Static Delay function.
Active Displays the active source for synchronizing the internal stereo coder
pilot tone
Options:
– OFF
– AES User Bits
– AES Start Frame
– Ext PPS
Static Delay For setting the MPX signal delay
Value range: 0
µ
s through 9 999 999.999
µ
s
Step size: 1 ns
e)
Pilot Phase For setting the pilot tone phase shift
f)
Value range: 0% through 100%
Step size: 0.01%
Clock Ref Possible selections
g)
:
– Internal
– External PPS
– External 10 MHz
– External AES
a) Can be used for sample rates 32, 44.1, 48, 88.2, 96, 176.4 and 192 kHz. The user bits must be set by the
operator in the AES signal as appropriate and should be the same in the left and right AES channels. The
change from "1" to "0" must be carried out in multiples of 1/19 kHz, e.g. for sample rates 44.4, 88.2 and 176.4
kHz, change from "1" to "0" at 1764 bit, and for sample rates 32, 48, 96 and 192 kHz, change from "1" to "0"
at 192 bit.
b) Start of block can only be used for sample rates 32, 48, 96 and 192 kHz. No further matching is necessary in
the AES signal.
c) User bits apply in the case of sample rates 44.1, 88.2 and 176.4 kHz; start of block is used for sample rates
32, 48, 96 and 192 kHz. The choice is made automatically according to the sample rate.
d) Can only be used when the SR8000-B2 "External Reference" option is installed.
e) Normal step size: 13.706 ns
f)
0% = 0°, 100% = 360° = 1/(19 kHz); the normal step size is 13.7 ns (approx. 0.026%). If the phase reference
signal and the audio data both come from the AES signal, you have the same delay time. The phase refer-
ence signal arrives in each exciter together with the same audio sample, and therefore the position of the
audio signal relative to the reference signal is the same in each exciter. The pilot tone phase is aligned on the
reference signal and therefore has the same position relative to the audio signal in each exciter. As a result
the MPX signals in all the exciters have the identical time characteristic. They are then only delayed relative
to the MPX signals of other exciters by the delay differences in the AES signal. On the other hand, since the
1 pps signal generated by a GPS receiver marks the start of a second, all exciters are therefore in synchro-
nicity. However, the audio signals are delayed relative to one another by delay differences in the various
exciters. The phase reference signal does not arrive in each exciter together with the same audio sample.
For this reason the pilot tone does not have the same position relative to the audio signals in each exciter,
and the time characteristic of the generated MPX signals is different in each exciter. In order to match the
phases of the pilot tones to the audio signals, resulting in MPX signals with identical time characteristics in
each exciter, the synchronization signal derived from the 1 pps signal is delayed as appropriate.
g) Alternately overwrites the corresponding setting in the Exciter > RF menu window. If the pilot tone is synchro-
nized with the AES signal (user bits or start of block), the AES signal should likewise be used as the clock ref-
erence. If the pilot tone is synchronized with the 1 pps signal from the GPS, a GPS signal (1 pps or 10 MHz)
should likewise be used as the clock reference.
Setting item Description