Chapter 6 ______________________________________________________ Processing Algorithms
VAISALA______________________________________________________________________ 187
6.1.2 RVP900 Receiver Modes
The RVP900 supports several receiver configurations which allow you to
choose the best style of IF processing for your particular site. The
following table summarizes the options from the Mc menu:
# Rx Mode Description
– –––––––––––––––––––––––
0 Standard single channel
1 ––Reserved––
2 Legacy RVP8/2005 WDN compatibility
3 Standard dual channel
- Mode-0: Standard Single Channel—This is the most common
"vanilla" mode that is used by single-polarization CW-pulsed radars
whose front-end LNA has a dynamic range less than ≤95 dB. The
(I,Q) data are computed from IF samples.
- Mode-1: Reserved—This mode is currently reserved for future
development, as they become necessary.
- Mode-2: Extra Wide Dynamic Range—Radars having very high
performance front-end LNAs can preserve the full benefit of that
investment by running two separate IF signals into the Primary
(HiGain) and Secondary (LoGain) IFDR inputs. A nominal channel
separation of 25 dB to 30 dB might be used to achieve an overall
dynamic range of up to 110 dB.
- Mode-3: Dual-Rx From Two IF Inputs—This is the standard dual
polarization mode in which the “H” and “V” channels are fed into two
separate IF inputs, both using the same intermediate frequency.
6.1.2.1 Discussion of Wide Dynamic Range Mode-2
When the RVP900 is used as an extended dynamic range receiver there are
some important decisions to make with respect to setting up the RF/IF
levels that drive the IFDR.
The first of these is the amount of signal level separation between the high
gain and the low gain IFDR inputs. There is an absolute minimum and
absolute maximum channel separation that still allows the IFDR to capture
the full dynamic range of the receiver. If a signal level separation is made
that is outside of these absolute limits valuable receiver dynamic range is
lost.
- The absolute minimum separation of the channels is equal to the total
dynamic range of the receiver minus the dynamic range of a single
channel of the IFDR. Generally, the total dynamic range of the
receiver is set by the LNA. For example, if we are considering a 1µ
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