Desired Vs. Actual Parameter Values

Desired vs. Actual in the SDRu Blocks

When you set mask values for center frequency, gain, interpolation factor, and decimation factor, the block performs rudimentary checks that the values are scalar and real. Even if your values pass those checks, you can still provide values that are out of range for the USRP®[1] hardware. In that case, the hardware makes a best effort to set the requested value, and reports the actual value in the block mask.

If the SDRu block is connected to USRP® hardware, you can check the block mask to find the acceptable ranges of center frequency and gain. The acceptable ranges of interpolation and decimation are integer values as follows:

Decimation factor, specified as an integer from 1 to 1024 with restrictions, based on the radio you are using.

ValueB-seriesN-seriesX-series

1

Not valid.

2

Acceptable when using int8 transport data type only.

3

Not valid.

Any number from 4 to 128

Any even number from 128 to 256

Any multiple of 4 from 256 to 512

Any multiple of 8 from 520 to 1024

Not valid.

Not valid.

The radio uses the decimation factor when downconverting the intermediate frequency (IF) signal to a complex baseband signal.

Interpolation factor, specified as an integer from 1 to 512 with restrictions, based on the radio you are using.

ValueB-seriesN-seriesX-series

1

Not valid.

2

Acceptable when using int8 transport data type only.

3

Not valid.

Any number from 4 to 128

Any even number from 128 to 256

Any multiple of 4 from 256 to 512

The radio uses the interpolation factor when upconverting the complex baseband signal to an intermediate frequency (IF) signal.

Desired vs. Actual in the SDRu System Objects

The default parameter values for the SDRu System objects are as follows:

  • IPAddress: 192.168.10.2

  • CenterFrequencySource: Property

  • CenterFrequency: 2450000000

  • ActualCenterFrequency: 0

  • LocalOscillatorOffsetSource: Property

  • LocalOscillatorOffset: 0

  • ActualLocalOscillatorOffset: 0

  • GainSource: Property

  • Gain: 8

  • ActualGain: 0

  • InterpolationFactorSource: Property

  • InterpolationFactor: 512

  • ActualInterpolationFactor: 0

  • UnderrunOutputPort: False

  • EnableBurstMode: False


[1] USRP, USRP2, UHD, and Ettus Research are trademarks of National Instruments Corp.