A Microwave Tuner in a VME-based Open Architecture, with Phase Coherent Multi-channel Operation
By Tyco Electronics

The TU-6401 VME tuner and TU-6402 frequency converter are the latest additions to a line of 0.1-40 GHz tuners and receivers from Tyco Electronics M/A-COM Products Group in Hunt Valley, Maryland (http://macom-sigint.com). Using direct synthesis of the local oscillator, the TU-6401 VME tuner is an excellent component for use in fast spectral search and multi-channel applications. This tuner can be used in a variety of sub-systems and payloads for next–generation SIGINT collection activities.

Applications
A central component in an EW/ ESM/ ELINT collection system is the microwave tuner. High probability of intercept (POI) and parameters that facilitate analysis of complex signals and frequency agile emitters are critical to the mission’s success for today’s spectral analysis environment. The TU-6401 full-band tuning speed of <75 µsec for a 0.5-18 GHz sweep ensures a fast time to intercept, and is a contributor to a high POI. Gain flatness of ±2 dB and differential group delay of ≤5 ns are keys to the tuner’s ability to support analysis of complex signals.

The TU-6401 VME tuner is also suitable for other ELINT tasks, such as collection, channelized system for high POI, and direction finding and TDOA applications. The tuner’s low weight and power consumption plus small size make it a good choice for unmanned vehicle platforms.

Performance and Multi channel Operation
The TU-6401 is a 2-slot, 6U VME module which converts signals in its 0.5 to 18 GHz tuning range to both narrowband and wideband IF outputs. The simultaneous analog outputs of 100 MHz BW and 500 MHz BW are centered at 160 MHz and 1 GHz, respectively. The analog IF outputs are suitable for direct input into an external A/D converter for special signal processing, spectral analysis, and pulse parameterization. Additionally, a log video port provides a third simultaneous analog output having a 20 MHz RF bandwidth and a nominal 0-2.5 V output level. Input to the log video detector is derived from the 160 MHz IF.

The TU-6401 is capable of supporting additional RF converter modules with control signals and a common synthesizer reference signal from its internal reference source. In a multiple RF converter configuration, the I2C bus is daisy-chained from the TU-6401 module to up to 15 additional TU-6402 RF converters (single-slot 6U modules). Likewise, an LO output from the TU-6401 is daisy-chained to the additional TU-6402 units.

External control of the TU-6401 is via 100BaseT Ethernet as well as through the VME bus. A graphical user interface (GUI) provides RF sweep and peak detection displays. Additional features are included in the GUI application to facilitate system configuration and Built-in-Test (BIT).

Design
The TU-6401 is a modular design. The tuner contains five distinct modules: system controller, RF converter, synthesizer, power supply, and reference generator. The TU-6402 leverages from this modular design by excluding the synthesizer and system controller, and packaging the remaining modules in a one-slot VME form. Multi-channel configuration greatly reduces the cost.

Specifications
In the ELINT environment, POI is very important and in a single tuner system, this is a direct function of the tuner’s ability to be rapidly tuned over a range of frequencies of interest. The TU-6401 VME tuner achieves increased sweep rates by an order of magnitude over existing M/A-COM SIGINT receivers using a distributed control design architecture and direct synthesis. This approach is achieved with distinct FPGAs residing in the individual subsystems. Through the combination of these common architectures, the TU-6401 achieves tuning times not previously attainable, as shown in Table 1.

As stated before, the important parameters for accurate signal analysis are gain linearity, group delay, and phase noise. Figures 2 and 3 illustrate the TU-6401’s outstanding performance in these areas.

Operating Modes
• The TU-6401 VME operates in either a CW (fixed tune mode) or various RF scanning modes. The following describes each mode of operation.

Fixed Tune Mode
• Tune to any frequency in the operating range with 1 kHz resolution at a change rate up to 500 frequencies per second.

RF Scan
Scan up to 128 arbitrary frequencies in a pre-defined order with a 1 kHz resolution at a change rate up to 500 frequencies per second.

Triggered RF Scan
• Dwell time is infinite, proceeds to next frequency only upon receipt of a Trigger Signal.

Auto RF Scan
• Tuner automatically proceeds to next frequency after specified dwell time.
Independent dwell time at each of the frequencies from 0 to 1 sec.

RF Sweep
• Sweep between any 2 frequencies with a minimum step size of 1 kHz. Step size is the same for the entire sweep.
• F2 >F1 as well as F1> F2 allowed. Spectrum Sense and IF attenuation are constant for all traces.

Auto RF Sweep
• Tuner automatically proceeds to next frequency after specified dwell time.
Dwell time selectable from 0 to 1 sec, constant for the entire sweep.

Triggered RF Sweep
Dwell time is infinite, proceeds to next frequency only upon receipt of a Trigger Signal.

Fast Sweep Speed, 0.5-18 GHz in 500 MHz steps, no dwell time
• Allows stepping across the full input band at the fastest possible speed of the hardware, sweep time <75 µsec.

Multi-Trace
• Up to 16 separate RF Sweeps.
• Triggered and Auto sweeps allowed in any combination.
• Independent step size and dwell time for all 16 traces.
• Spectrum Sense and IF attenuation are constant for all traces.

System Operation
• Integrated signal level detector
• 80 dB dynamic range nominal
• Coupled to A/D for digitization
• Permits user-defined threshold settings for sweep, scan, and fixed tune (flagging) operational modes.
• 128 RF scan presets have independent threshold setting for each.
• Multi-Trace Mode allows sixteen traces with unique 10-bit threshold value for each trace.

Auto Stop
• Tuner halts a single or multi-trace RF Sweep or an RF Scan upon detection of a signal level exceeding a pre-defined level at the 160 MHz IF and notifies the controller with level and frequency.

Hit List Generation
• Same as Auto Stop, but the sweep or scan is not stopped.
• The number of hits at a frequency is collected and passed to the host.
• The hits continue to accumulate until reset by a command.

Conclusion
Both in strategic INTEL and military tactical environments, the current need is for more modular and rugged system solutions that can scan, collect and analyze today’s spectral environment faster. The TU-6401 VME tuner is a key addition to the collection systems market. The TU-6401 reduces size, weight, and power (SWaP) and still maintains performance comparable to that of conventional high performance microwave receivers. In addition, the assembly of TU-6402s in a multi-channel configuration greatly reduces cost without affecting performance.

Tyco Electronics
www.tycoelectronics.com
TXTLINX.COM93
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