RFR Series

The RFR series of RF data record/playback systems allows users to record RF signals at frequencies up to 2.7 GHz with 20 MHz bandwidth for over 4 hours. The recorded signals can then be played back on demand to simulate the recorded signal. These systems are developed on the PXI platform to ensure expandability, longevity, and the ability to integrate with other testing requirements.

Applications

The RFR series was designed to support RF testing in applications where the source signal is not readily available in the lab where units must be tested. For example, to test satellite radio receivers under different weather/terrain conditions this system allows a user to drive through different environments in varying weather conditions while recording the target signal. The data module is then returned to the lab where the files can be played back to units under test (UUTs) at will, removing any seasonal or geographic constraints from testing and development.

Specifications

• 250 kHz to 2.7 GHz
• 20 MHz real-time bandwidth
• 14 bit resolution
• +/- 20 ppb frequency stability
• -130 dBm to +10 dBm

RFR System Design

Both the record and playback functions are accomplished by combining the superior accuracy and flexibility of National Instruments' (NI) PXI RF equipment with Conduant's ultra-high speed, long duration recording technology.

The source signal is routed into a RF preamplifier to adjust the signal level as needed. The amplified signal is then routed to the 2.7 GHz down-converter to convert the signal to IF (intermediate frequency). The IF signal is then digitized at 50 MS/s. The digital data is then routed through the Conduant system directly to a hard drive array which can hold up to 4.4 hours of RF data.Once the data is recorded, the hard drive array is removed from the record system and connected to the playback system. To play the signal back the hard drive array streams the data across the PXI bus to an Arbitrary Waveform Generator which generates the IF signal. The IF signal is then routed to an up-converter which converts the IF signal to the required RF frequency.

RFR System Options

A wide range of flexibility is achieved by utilizing the PXI platform in order to meet differing test needs. The basic system is comprised of two separate systems: a record system and a playback system. This allows one group to record signals in the field while another group uses previously recorded signals for testing and development.

RFR 5001 RF Data Portable Record System
The portable record system is intended to be used in the field to record over-the-air signals in a mobile environment. As such, the PXI chassis and all required hardware are enclosed in a shock mounted, shippable case. In addition to the RF recording system, a GPS card is utilized to record position data that can be correlated with the recorded signal.

RFR 5002 RF Data Playback System
The playback system is generally used in a laboratory environment and as such is not designed to be portable. This system can be used either as a desktop or as a rack-mount unit.

RFR 5005 RF Data Record/Playback System
This system combines both the RFR 5001 and RFR 5002 systems into a single system for applications where the recording and playback processes do not need to happen at separate locations or at the same time. This system can be used either as a 5001 or as a 5002 but cannot do both simultaneously. This system provides a slight cost savings by using only one PXI chassis and controller. Like the 5002, this system is designed for desktop or rack-mount use and can also be mounted in a shock mounted, shippable case.

RFR 5021 Dual Channel Portable Record System
This variation allows two channels to be simultaneously recorded to two hard drive arrays for situations where signals at two different frequencies are required or the same signal is to be acquired through two separate antennas.

RFR 5022 Dual Channel Playback System
This is the compliment to the 5021 and allows simultaneous playback of two channels at the same or different frequencies.

Software Operation

One set of software runs each of the RFR variations by automatically sensing which components are present in the system and customizing the user interface accordingly.

For record operations, the user simply inputs the basic settings such as center frequency, resolution bandwidth, real-time bandwidth, and a filename. After these settings are entered, the software functions similar to a VCR or DVR with record, play, pause, and stop buttons.

In addition, basic analysis views are available to view recorded files in either a standard spectrum analyzer view or in a waterfall plot.

Utilities are provided to move files from the hard drive arrays to the local drive or external storage for external analysis and/or modification. Files can also be moved onto the hard drive arrays from external sources in order to play synthesized or modified signals.

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RFR Series

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