Difference between revisions of "TwinRX"

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Revision as of 19:37, 8 August 2016

Device Overview

The TwinRX daughterboard for the USRP X Series SDR platform is a two-channel superheterodyne receiver designed for high performance spectrum monitoring and direction finding applications. The receiver is tunable from 10 MHz - 6 GHz and has 80 MHz of instantaneous bandwidth per channel, providing the versatility nessary to analyze a variety of signals in multiple bands of interest. Each channel has an independent RF signal chain with preampilifiers, preselectors, and two mixer stages for superior selectivity. Users can tune the two channels independently to simultaneously montior uplink and downlink communication with a combined bandwidth of 160 MHz. The ability to share the LO between channels across multiple daughterboards enables the phase-aligned operation required to implement scalable multi-channel phased-arrays. The receiver is capable of fast frequency hopping to detect frequency agile emitters. Configurable RF attenuation and preamplication allow users to optimize dynamic range in favor of noise figure for faint signals, or IP3 for stronger signals. UHD automatically configures the RF signal path for optimized performance in the pre-defined use cases, and provides the flexibility to adjust settings manually. Support for RFNoC on the X Series motherboard enables deterministic FPGA-accelerated computations for real-time spectrum analysis.

TwinRX BlockDiagram.png


Key Features

  • Two-Channel Superheterodyne Receiver
  • Frequency Range: 10 MHz - 6 GHz
  • Bandwidth: 80 MHz per channel ( 160 MHz total )
  • RF shielding
  • Independent RF signal channels with optional LO sharing
TwinRX large.png

Daughterboard Specifications

Features

  • 2 superheterodyne frontends (2 receive)
  • 80 MHz per channel
  • Independent tuning
  • LO Sharing Capability
  • Coherent and phase-aligned operation
  • Preselection Filters
  • RF Shielding

Antennas

Receive: RX1 or RX2

Gains

  • Receive Gains Range: 0-95dB

Bandwidths

  • TwinRX: 80 MHz per channel ( 160 MHz total )

Sensors

  • lo_locked: boolean for LO lock state

Ports

The TwinRX has six MMCX RF connectors on it.

Connector Description Damage Threshold/Max Output
J1 LO2 Export 0 dBm output
J2 LO2 Input +20dBm input
J3 LO1 Export +5 dBm output
J4 LO1 Input +10dBm input
J5 Antenna 1 connector (RX1) +10 dBm input
J6 Antenna 2 connector (RX2) +10 dBm input

Preselector Filters

Band Range
LB1 10 - 500 MHz
LB2 500 - 800 MHz
LB3 800 - 1.2 GHz
LB4 1.2 - 1.8 GHz
HB1 1.8 - 3.0 GHz
HB2 3.0 - 4.1 GHz
HB3 4.1 - 5.1 GHz
HB4 5.1 - 6.0 GHz
  • Each preselector filter has a ±40 MHz band overlap.


RF Specifications

Freq Range

  • 10MHz - 6GHz

Noise Figure

Frequency Preamp Enabled
10 MHz - 3 GHz < 5
3 GHz - 5 GHz < 4
5 GHz - 6 GHz < 8

RX Third Order Intercept (dBm)

Frequency Full Scale = -45 dBm Full Scale = -30 dBm Full Scale = -20 dBm
10 MHz - 1.8 GHz -8 -2 16
1.8 GHz - 3 GHz -10 -1 14
3 GHz - 6 GHz -13 -1 12


Phase Noise (dBc/Hz)

Frequency Offset 0.9 GHz 2.4 GHz 5.8 GHz
10 kHz -88 -86 -82
100 kHz -105 -107 -103
1 MHz -124 -127 -127

Hardware Specifications

  • Ettus Research recommends to always use the latest stable version of UHD. Minimum UHD version is 3.10.0.0

TwinRX

  • Current Hardware Revision: 2
  • Minimum version of UHD required: 3.10.0.0
  • Minimum version of GNU Radio required: 3.7.10

Environmental Specifications

Operating Temperature Range

  • 0-40 °C

Operating Humidity Range

  • 10% to 90% non-condensing

USRP Compatibility

  • X Series only

Schematics

The TwinRX daughterboard is composed of two PCBs, the Intermediate Frequency (IF) board and the RF board. There are two functionally identical revisions of TwinRX at the moment. Please check the back of your TwinRX to see which you have. The schematics for TwinRX revision B should answer most possible questions. If you have any further questions please email support@ettus.com.

TwinRX Revision A - (159685A-01)

  • IF Board Revision B - (158671B-01L)
  • RF Board Revision C - (156263C-01L)

TwinRX Revision B - (159685B-01)

  • IF Board Revision C - (158671C-01L)
  • RF Board Revision D - (156263D-01L)

File:TwinRX IF Board Rev C.pdf

File:TwinRX RF Board Rev D.pdf

RF Connectors

The antenna ports are MMCX connectors with 50 ohm input impedance. By default Antenna 1 (RX1) is routed to Channel 1 and Antenna 2 (RX2) to Channel 2. This routing can be changed to swap the antennas or to share a single antenna to both channels. The damage threshold for the antenna inputs is 10 dBm. In practice the available gain makes much lower input powers recommended for achieving the best dynamic range and noise figure.

TwinRX 80 Inputs.jpg

Local Oscillator Connectors

Connector Description Min Nominal Damage
J1 LO2 Export 0 dBm 0 dBm NA (Output)
J2 LO2 Input 0 dBm +20dBm
J3 LO1 Export -12 dBm +5 dBm NA (Output)
J4 LO1 Input -10 dBm -5 dBm +10dBm
TwinRX 80 LOs.jpg

LO Sharing with Neighbour TwinRXs

TwinRX (A Slot) TwinRX (B Slot)
J1 LO2 Export J2 LO2 Input
J2 LO2 Input J1 LO2 Export
J3 LO1 Export J4 LO1 Input
J4 LO1 Input J3 LO1 Export

Certifications

RoHS

As of December 1st, 2010 all Ettus Research products are RoHS compliant unless otherwise noted. More information can be found at http://ettus.com/legal/rohs-information

Downloads

FPGA Resources

UHD Stable Binaries

UHD Source Code on Github