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The gain of the converter can be set to have no gain (0dB) at maximum attenuation or
a gain of 30dB at minimum attenuation. The finite gain set is specified to be within 2dB
of the setting and the step size is 0.1dB.
1.3.10 Gain flatness
±1.5dB full band, ±0.5dB, across any 36MHz in band
The slope and variation of power across the L/ S-Band should be within 2dB top to
bottom, but within 1dB across any 36MHz.
1.3.11 1dB Gain Compression Point
Output +10dBm, Input -10dBm
The 1dB compression point is a finite point in the power scale where a 1dB input only
gives 0.5dB increase in power. At a gain of +20dB the output stage of the unit will
compress before the input stage and conversely at gains of less than 20dB the input
stage will compress before the output stage. Note also the values specified are for total
composite power and not single carrier.
1.3.12 UpConverter Output spurious
<-60dBm (in band non-carrier related), <-60dBc (in band carrier related)
All converters generate spurious signals due to Local Oscillator leakage inside the unit
and possibly some mixing products of these oscillators. These signals are always
present to some degree and are not related to the carrier signal being present so are
specified as a maximum finite power in dBm and are always measured at full gain.
Other signals associated with the carrier are also specified but relative to the carrier
(dBc) and again measured at full gain. During manufacture only out of band signals in
the minimum /2 and maximum x2 range are considered. Note that these spurii will be
seen to change in finite value when gains other than full gain are selected due to
switching of internal attenuators.
A typical setup is to set a converter input power of -20dBm and an output of 0dBm.
Consideration of spurii should be made if the input power is significantly reduced as low
input power will give a worse spurious to signal ratio.
1.3.13 Invert Spectrum
In a conversion process if the Local oscillator used is of a higher frequency than the
Input frequency then the output will be spectrum inverted. This means that the High
Frequency side of an FM signal will come out at the Low Frequency side of the centre
frequency. To decode a signal the decoder must know whether the signal is inverted
and somewhere in the system there must be a mechanism to re-invert the signal.
A classical example is the 5.15GHz oscillator used in a C-Band LNB. To convert the 3.4
to 4.2GHz band to 950MHz to 1750MHz a 2.45GHz LO is the calculated frequency.
Unfortunately this 2.45GHz LO gives a problem due to twice the LO mixing with the
input to give an interfering signal (4.9-3.4=1.5). A 5.15GHz LO is therefore used to
avoid this problem and consequently the L-Band to 70MHz converter (P7001R) has to
have INVERT enabled to preserve the spectrum. It is not normal to transmit inverted.
1.3.14 Auxiliary DC output.
Page 8
P7001R & P7002R Series Converters
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