# UHD - Daughterboard Application Notes

Table of Contents

- Daughterboard Properties
  - Basic RX and LFRX
  - Basic TX and LFTX
  - DBSRX
  - DBSRX2
  - RFX Series
  - XCVR 2450
  - WBX Series
  - SBX Series
  - TVRX
  - TVRX2
- Daughterboard Modifications
  - DBSRX - Mod
  - RFX - Mod

# Daughterboard Properties

The following contains interesting notes about each daughterboard. Eventually, this page will be expanded to list out the full properties of each board as well.

## Basic RX and LFRX

The Basic RX and LFRX boards have 4 frontends:

- Frontend A: real signal on antenna RXA
- Frontend B: real signal on antenna RXB
- Frontend AB: quadrature frontend using both antennas (IQ)
- Frontend BA: quadrature frontend using both antennas (QI)

The boards have no tunable elements or programmable gains. Through the magic of aliasing, you can down-convert signals greater than the Nyquist rate of the ADC.

BasicRX Bandwidth (Hz):

- For Real-Mode (A or B frontend): 250M
- For Complex (AB or BA frontend): 500M

LFRX Bandwidth (Hz):

- For Real-Mode (A or B frontend): 33M
- For Complex (AB or BA frontend): 66M

## Basic TX and LFTX

The Basic TX and LFTX boards have 4 frontends:

- Frontend A: real signal on antenna TXA
- Frontend B: real signal on antenna TXB
- Frontend AB: quadrature frontend using both antennas (IQ)
- Frontend BA: quadrature frontend using both antennas (QI)

The boards have no tunable elements or programmable gains. Through the magic of aliasing, you can up-convert signals greater than the Nyquist rate of the DAC.

BasicTX Bandwidth (Hz): 250M

- For Real-Mode (A or B frontend): 250M
- For Complex (AB or BA frontend): 500M

LFTX Bandwidth (Hz): 33M

- For Real-Mode (A or B frontend): 33M
- For Complex (AB or BA frontend): 66M

## DBSRX

The DBSRX board has 1 quadrature frontend. It defaults to direct conversion but can use a low IF through lo_offset in uhd::tune_request_t.

Receive Antennas: J3

- Frontend 0: Complex baseband signal from antenna J3

The board has no user selectable antenna setting.

Receive Gains:

- GC1, Range: 0-56dB
- GC2, Range: 0-24dB

Bandwidth (Hz): 8M-66M

Sensors:

- lo_locked: boolean for LO lock state

## DBSRX2

The DBSRX2 board has 1 quadrature frontend. It defaults to direct conversion, but can use a low IF through lo_offset in uhd::tune_request_t.

Receive Antennas: J3

- Frontend 0: Complex baseband signal from antenna J3

The board has no user-selectable antenna setting.

Receive Gains:

- GC1, Range: 0-73dB
- BBG, Range: 0-15dB

Bandwidth (Hz): 8M-80M

Sensors:

- lo_locked: boolean for LO lock state

## RFX Series

The RFX Series boards have 2 quadrature frontends: Transmit and Receive. Transmit defaults to low IF, and Receive defaults to direct conversion. The IF can be adjusted through lo_offset in uhd::tune_request_t.

The RFX Series boards have independent receive and transmit LO's and synthesizers allowing full-duplex operation on different transmit and receive frequencies.

Transmit Antennas: TX/RX

Receive Antennas: TX/RX or RX2

- Frontend 0: Complex baseband signal for selected antenna

The user may set the receive antenna to be TX/RX or RX2. However, when using an RFX board in full-duplex mode, the receive antenna will always be set to RX2, regardless of the settings.

Receive Gains: PGA0, Range: 0-70dB (except RFX400 range is 0-45dB)

Bandwidths (Hz):

- RX: 40M
- TX: 40M

Sensors:

- lo_locked: boolean for LO lock state

## XCVR 2450

The XCVR2450 has 2 quadrature frontends, one transmit, one receive. Transmit and Receive default to direct conversion but can be used in low IF mode through lo_offset in uhd::tune_request_t

The XCVR2450 has a non-contiguous tuning range consisting of a high band (4.9-6.0GHz) and a low band (2.4-2.5GHz).

Transmit Antennas: J1 or J2

Receive Antennas: J1 or J2

- Frontend 0: Complex baseband signal for selected antenna

The XCVR2450 uses a common LO for both receive and transmit. Even though the API allows the RX and TX LOs to be individually set, a change of one LO setting will be reflected in the other LO setting.

The XCVR2450 does not support full-duplex mode, attempting to operate in full-duplex will result in transmit-only operation.

Transmit Gains:

- VGA, Range: 0-30dB
- BB, Range: 0-5dB

Receive Gains:

- LNA, Range: 0-30.5dB
- VGA, Range: 0-62dB

Bandwidths (Hz):

- RX: 15M, 19M, 28M, 36M; (each +-0, 5, or 10%)
- TX: 24M, 36M, 48M

Sensors:

- lo_locked: boolean for LO lock state
- rssi: float for rssi in dBm

## WBX Series

The WBX Series boards have 2 quadrature frontends, one transmit, one receive. Transmit and Receive default to direct conversion but can be used in low IF mode through lo_offset in uhd::tune_request_t.

The WBX Series boards have independent receive and transmit LO's and synthesizers allowing full-duplex operation on different transmit and receive frequencies.

Transmit Antennas: TX/RX

Receive Antennas: TX/RX or RX2

- Frontend 0: Complex baseband signal for selected antenna

The user may set the receive antenna to be TX/RX or RX2. However, when using an WBX board in full-duplex mode, the receive antenna will always be set to RX2, regardless of the settings.

Transmit Gains: PGA0, Range: 0-25dB

Receive Gains: PGA0, Range: 0-31.5dB

Bandwidths (Hz):

- RX: 40M
- TX: 40M

Sensors:

- lo_locked: boolean for LO lock state

## SBX Series

The SBX Series boards have 2 quadrature frontends, one transmit, one receive. Transmit and Receive default to direct conversion but can be used in low IF mode through lo_offset in uhd::tune_request_t.

The SBX Series boards have independent receive and transmit LO's and synthesizers allowing full-duplex operation on different transmit and receive frequencies.

Transmit Antennas: TX/RX

Receive Antennas: TX/RX or RX2

- Frontend 0: Complex baseband signal for selected antenna

The user may set the receive antenna to be TX/RX or RX2. However, when using an SBX board in full-duplex mode, the receive antenna will always be set to RX2, regardless of the settings.

Transmit Gains: PGA0, Range: 0-31.5dB

Receive Gains: PGA0, Range: 0-31.5dB

Bandwidths (Hz):

- RX: 40M
- TX: 40M

Sensors:

- lo_locked: boolean for LO lock state

LEDs:

- All LEDs flash when dboard control is initialized
- TX LD: Transmit Synthesizer Lock Detect
- TX/RX: Receiver on TX/RX antenna port (No TX)
- RX LD: Receive Synthesizer Lock Detect
- RX1/RX2: Receiver on RX2 antenna port

## TVRX

The TVRX board has 1 real-mode frontend. It is operated at a low IF.

Receive Antennas: RX

- Frontend 0: real-mode baseband signal from antenna RX

Receive Gains:

- RF, Range: -13.3-50.3dB (frequency-dependent)
- IF, Range: -1.5-32.5dB

Bandwidth: 6MHz

## TVRX2

The TVRX2 board has 2 real-mode frontends. It is operated at a low IF.

Receive Frontends:

- Frontend RX1: real-mode baseband from antenna J100
- Frontend RX2: real-mode baseband from antenna J140

Note: The TVRX2 has always-on AGC; the software controllable gain is the final gain stage which controls the AGC set-point for output to ADC.

Receive Gains:

- IF, Range: 0.0-30.0dB

Bandwidth: 1.7MHz, 6MHz, 7MHz, 8MHz, 10MHz

Sensors:

- lo_locked: boolean for LO lock state
- rssi: float for measured RSSI in dBm
- temperature: float for measured temperature in degC

# Daughterboard Modifications

Sometimes, daughterboards will require modification to work on certain frequencies or to work with certain hardware. Modification usually involves moving/removing an SMT component and burning a new daughterboard ID into the EEPROM.

## DBSRX - Mod

Due to different clocking capabilities, the DBSRX will require modifications to operate on a non-USRP1 motherboard. On a USRP1 motherboard, a divided clock is provided from an FPGA pin because the standard daughterboard clock lines cannot provided a divided clock. However, on other USRP motherboards, the divided clock is provided over the standard daughterboard clock lines.

Step 1: Move the clock configuration resistor

Remove R193 (which is 10 ohms, 0603 size), and put it on R194, which is empty. This is made somewhat more complicated by the fact that the silkscreen is not clear in that area. R193 is on the back, immediately below the large beige connector, J2. R194 is just below, and to the left of R193. The silkscreen for R193 is ok, but for R194, it is upside down, and partially cut off. If you lose R193, you can use anything from 0 to 10 ohms there.

Step 2: Burn a new daughterboard id into the EEPROM

With the daughterboard plugged-in, run the following commands:

    cd <install-path>/share/uhd/utils
    ./usrp_burn_db_eeprom --id=0x000d --unit=RX --args=<args> --slot=<slot>

- <args> are device address arguments (optional if only one USRP is on your machine)
- <slot> is the name of the daughterboard slot (optional if the USRP has only one slot)

## RFX - Mod

Older RFX boards require modifications to use the motherboard oscillator. If this is the case, UHD will print a warning about the modification. Please follow the modification procedures below:

Step 1: Disable the daughterboard clocks

Move R64 to R84. Move R142 to R153.

Step 2: Connect the motherboard blocks

Move R35 to R36. Move R117 to R115. These are all 0-ohm, so if you lose one, just short across the appropriate pads.

Step 3: Burn the appropriate daughterboard ID into the EEPROM

With the daughterboard plugged-in, run the following commands:

    cd <install-path>/share/uhd/utils
    ./usrp_burn_db_eeprom --id=<rx_id> --unit=RX --args=<args> --slot=<slot>
    ./usrp_burn_db_eeprom --id=<tx_id> --unit=TX --args=<args> --slot=<slot>

- <rx_id> choose the appropriate RX ID for your daughterboard
  - RFX400: 0x0024
  - RFX900: 0x0025
  - RFX1800: 0x0034
  - RFX1200: 0x0026
  - RFX2400: 0x0027
- <tx_id> choose the appropriate TX ID for your daughterboard
  - RFX400: 0x0028
  - RFX900: 0x0029
  - RFX1800: 0x0035
  - RFX1200: 0x002a
  - RFX2400: 0x002b
- <args> are device address arguments (optional if only one USRP is on your machine)
- <slot> is the name of the daughterboard slot (optional if the USRP has only one slot)