Specifications

The BER also depends on the mix of AM, FM and QAM channels. If the QAM load is very
small compared to the AM and FM load the OMItotrms might be chosen about 1 dB
higher while still obtaining the BER as given in the diagram below.
1.00E+00
OMI
totrms
in %
externally modulateddirect
modulated
25.0 22.520.017.5 15.0
1.00E-02
1.00E-04
1.00E-06
1.00E-08
1.00E-10
The ES10 is typically factory adjusted to achieve a BER of 10
-9
with most frequency plans
using the built in AGC function.
Experienced users are free to change the factory preadusted OMItotrms by up to +3 / -3
dB in steps of 0.2 dB and/or to use the ES10 in non-AGC mode. This gives the flexibility
to optimize the total system CNR or CSO/CTB performance.
5.2.2 Mode: AGC-on, modulated carriers (user adjustable)
There is an alternative AGC mode available for measurement purposes only: AGC-on for
modulated carriers. This mode is only required when measuring CXMA (cross
modulation distortions) in HFC networks and should not be used in normal operations
of HFC networks.
In CXMA measurements, with AGC on the RF signal is increased by about 3 dB, due to
the typical 100% duty cycle in cross modulation measurements. This leads, however, to
rather poor CXMA values measured with AGC-on. In order to compensate for the
increased gain in CXMA measurement, the AGC-on mode for modulated carriers has
been implemented. Compared to the AGC-on mode for unmodulated CW carriers, the
gain is decreased by about 3 dB for measurement purposes only.
5.2.3 Mode: AGC-off, (user adjustable)
In this mode, which is for experienced users only, the user has the flexibility to change
the gain of the internal RF amplifier by +3 / -6 dB according to his own requirements.
The OMItotrms is measured for the applied input signal and selected gain and can be
monitored on the LCD or via the Ethernet interface.
This mode should only be used with great care since the automatic protection against
overmodulation as given in the AGC-on mode is lost.
5.3 ITU frequency adjustments in DWDM applications (ES10-XLa only)
The ES10 offers to tune the optical frequency (respectively wavelength) of the
transmitter by +/-100 GHz in steps of 50 GHz in order to enable DWDM applications.
The tuning can be perfomed via the buttons on the front panel or via the Ethernet
interface.
Funea Broadband Services bv product information page 23 of 31
version: 11-02