Installation Instructions

Hardware Installation
RVP8 User’s Manual
September 2005
2–18
for the data pairs and outer cable shield. In most radar applications it is highly recommended
that shielded twisted pair cable be used rather than the more common unshielded variety. The
DC shield ground is established only at the RVP8/Rx side to avoid ground loops between the
IFD and PCI chassis.
Three of the four CAT-5E twisted pairs are used as dedicated downlink channels, and the fourth
pair carries a dedicated uplink channel. Thus, each driver/receiver operates in a single direction
only, i.e., the data direction is fixed on each wire pair. The RJ-45 connector on both the IFD and
Rx cards is a Gigjack T12 (JK0-0016 from Pulse Engineering, www.pulseeng.com).
S The three downlink channels are identical and use RJ-45 line pairs MX1, MX2 and MX3.
Each line is driven from the PECL outputs of a Cypress CY7B923 “Hotlink” transmitter
via 33W series resistors. Each transmitter chip produces an independent 360MBaud data
stream using 8B/10B encoding, yielding an aggregate line rate of 1080MBaud (payload
rate of 864MBaud). The spectral characteristics of each downlink twisted pair can be
predicted entirely from this baud rate and encoding technique. Maximum differential
delay (propagation skew) among the three downlink pairs must be less than 25ns.
S The single uplink channel uses RJ-45 line pair MX4, and is driven by a PECL transmitter
having 33W series output resistors. The uplink data rate is 72MBaud, and is presented in
a manner having nearly the same spectral characteristics as Manchester encoding.
The exact content of the four CAT-5E data streams is beyond the scope of this manual, but the
above descriptions should be sufficient to understand the bandwidth and electrical properties of
the signals on each twisted pair. This information is applicable for cable selection, or toward the
design of a repeater to carry the CAT-5E signals over different media.
2.2.14 Summary of Crystal and Filter Configurations
The RVP8/Rx, RVP8/Tx and IFD can operate in many different clocking and sampling
configurations, depending on the requirements of the radar in which they are installed. The
following summary describes how to setup the crystals and filters in your equipment.
Step 1. Choose the Intermediate Frequency
Custom analog bandpass filters are installed in the RVP8/Tx and IFD to match to the radar’s
Intermediate Frequency. The RVP8/Tx filters are soldered directly onto the PCI card and are not
really meant to be changed by the user. The IFD filters, however, attach via coax cables and are
located on a serviceable mounting plate attached to the IFD.
Simply verify that the center frequency of all of your bandpass filters match the IF of your radar.
Our standard filter frequencies are: 16MHz, 30MHz, 57.5MHz, and 60MHz.
Step 2. Choose Clock Locking Options
The RVP8 acquisition and trigger clocks can operate as free-running oscillators, or they can be
phase locked to an external reference signal.
S For simple magnetron radars there is generally no system reference clock, and the
free-running clock mode is therefore appropriate. However, if a synthesized STALO is