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™ 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 for the SDRu receiver, specified as an integer from 1 to 1024 with restrictions, based on the radio you use.

DecimationFactor Property ValueB-SeriesN2xx-SeriesN3xx-SeriesX-Series

1

Valid

Not valid

Valid

Not valid when connected with TwinRX daughterboard

2

Valid

Acceptable when you use only the int8 transport data type

Valid

Valid

3

Valid

Not valid

Valid

Valid

Odd number from 4 to 128

Valid

Valid

Not valid

Valid

Even number from 4 to 128

Valid

Valid

Valid

Valid

Even number from 128 to 256

Valid

Valid

Valid

Valid

Multiple of 4 from 256 to 512

Valid

Valid

Valid

Valid

Multiple of 8 from 512 to 1024

Not valid

Not valid

Valid

Valid

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

Interpolation factor for the SDRu transmitter, specified as an integer from 1 to 1024 with restrictions, based on the radio you use.

InterpolationFactor Property ValueB-SeriesN2xx-SeriesN3xx-SeriesX-Series

1

Valid

Not valid

Valid

Valid

2

Valid

Acceptable when you use only the int8 transport data type

Valid

Valid

3

Valid

Not valid

Valid

Valid

Odd number from 4 to 128

Valid

Valid

Not valid

Valid

Even number from 4 to 128

Valid

Valid

Valid

Valid

Even number from 128 to 256

Valid

Valid

Valid

Valid

Multiple of 4 from 256 to 512

Valid

Valid

Valid

Valid

Multiple of 8 from 512 to 1024

Not valid

Not valid

Valid

Not valid

The radio uses the interpolation factor when it upconverts 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