Weighing only 23 pounds and measuring just 16″ W x 5.7″ D x 11.5″ H, nevertheless, Pentek’s Model RTS 2721 Portable Signal Recording and Playback Instrument delivers truly remarkable performance. With recording and playback rates up to 500 MB/second, the unit is well suited for a broad range of communications and radar applications that require acquisition, down conversion, analysis, up conversion and reproduction of baseband and IF signals.
“The RTS 2721 is especially valuable for our government and military customers who need a highly portable instrument to record or reproduce wideband analog signals. This compact instrument delivers the superior signal quality and real-time data rates that were previously attainable only from our larger VME systems,” says Rodger Hosking, vice president of Pentek.
Recording and Playback at Exceptionally High Data Rates
The RTS 2721 incorporates Pentek’s high-performance Model 7641 Software Radio Transceiver for A/D and D/A conversion and for digital down- and up-conversion. Two 14-bit A/D converters digitize two analog input signals at sample rates up to 125 MHz, thus handling either IF input signals with center frequencies as high as 300 MHz or baseband signals up to 60 MHz.
Multiple digital down converters (DDCs) translate tunable frequency slices of the input spectrum down to baseband and then filter the output. With programmable DDC decimation factors from 2 to 65536, DDC output signal bandwidths can range from 2 kHz to as high as 60 MHz.
Both A/D samples and DDC output samples can be recorded continuously in real time to internal hard disk RAID arrays at aggregate sustained rates up to 500 MB/sec. Flexible modes support synchronous multi-channel recording for beamforming applications, and independent recording of multiple channels, each at different data rates.
Playback operation allows analog reproduction of digital signals stored on the RAID disk array through two 16-bit D/A converters. At sustained playback data rates up to 480 MB/sec, digital sample streams can be delivered to the D/A converters using a variety of useful output modes.
First, the D/A converters can be driven directly from stored sample streams at up to 120 Msamples/sec, producing two baseband outputs, each with a bandwidths up to 60 MHz.
Secondly, built-in interpolation filters can be used to boost baseband sampling rates to higher D/A sampling rates by a factor of x2 to x32768 for optimum smoothing of the analog output waveform. In this mode, the maximum output sample rate can be as high as 500 MHz.
Thirdly, a digital up converter (DUC) can translate real or complex recorded baseband signals up to IF center frequencies as high as 160 MHz, with a maximum output sample rate of 320 MHz. The interpolation filters facilitate translation of recorded baseband signals with bandwidths from audio up to 60 MHz.
Pentek’s previous RTS 2500 Series VME systems handled peak data record and playback rates of 160 MB/second. “Now with the RTS 2721, that rate has more than tripled to 500 MB/second – a substantial jump, especially considering that it’s a portable instrument,” says Hosking. “With its extremely wide range of bandwidths, plus the ability to handle either baseband or IF signals for both input and output signals, this versatile instrument is directly compatible with a wide range of communication and radar systems.”
A Full-Featured Portable Workstation
Built around a Windows XP Professional workstation with a dual core Opteron processor and integral high-resolution 17-inch LCD display, the RTS 2721 records data using the native NTFS file system, providing immediate access to the recorded data. Data can be transferred from and to the instrument via triple GigENET ports, two external SATA II ports, or four USB 2.0 ports. Additionally, data can be transferred using the 8x double layer DVD ±R / RW drive.
Users can install their own Windows applications and tools to perform data analysis, post-processing, signal synthesis or any other applications that they might find useful in a portable environment.
Fully supported by Pentek’s Model 4990 SystemFlow Instrument Software, the RTS 2721 features a Windows-based GUI (graphical user interface) that provides a simple means to configure and control the instrument. Virtual instrument push buttons, status indicators, pull down menus and data parameter entry windows provide simple and intuitive operation for all functions, plus extended support for complex record/playback modes. Custom configurations can be stored as profiles and later loaded when needed, allowing the user to select pre-configured instrumentation settings with a single click.
SystemFlow Signal Viewer
SystemFlow also includes a powerful signal viewing and analysis tool, so the user can monitor signals both prior to and during a recording session. The SystemFlow Signal Viewer includes a virtual oscilloscope and a virtual spectrum analyzer for detailed signal analysis in both time and frequency domains. It is extremely useful for previewing live inputs prior to recording and for monitoring signals as they are being recorded to help ensure successful recording sessions. The viewer can also be used to inspect and analyze the recorded files after recording is complete.
Advanced signal analysis capabilities include automatic calculators for signal amplitude and frequency, second and third harmonic components, THD (total harmonic distortion) and SINAD (signal to noise and distortion). With time and frequency zoom, panning modes and dual annotated cursors to mark and measure points of interest, the SystemFlow Signal Viewer can often eliminate the need for a separate oscilloscope or spectrum analyzer in the field.
2.4 Terabytes of Disk Storage Ensures No Data Loss
Packed into the RTS 2721 enclosure are thirteen 2.5-inch hard drives, one of which handles the operating system. The other twelve drives are configured as dual RAID arrays, dedicated exclusively for real time recording and playback functions. This architecture guarantees no loss of data for sustained operation at the maximum rates, and delivers a total storage capacity of 2.4 terabytes. As an example, this capacity supports continuous, real-time recording of a single 100 MHz A/D channel for 3 hours and 20 minutes.
What Sets the RTS 2721 Apart From the Competition
Traditionally, companies tackle high-speed recording requirements by streaming data to disk using a proprietary file format. The disadvantage with this scheme is that after recording, the proprietary files must be converted to a Windows or Linux file, an operation often taking as much time as the original recording itself.
In the RTS 2721, Pentek records the data files directly to a native NTFS file system, fully compatible with every Windows file system and many Linux operating systems. This means users can access files immediately after recording, with no lengthy conversion processing. The same benefit applies to files generated for playback, since the RTS 2721 accepts NTFS files directly for playback with no pre-processing file conversion required.