Desired Versus Actual Parameter Values

Desired Versus Actual Value in Receiver Block

For the RTL-SDR Receiver block, when you specify the parameter values to set the center frequency, sample rate, and frequency correction, the block initially performs rudimentary checks to verify that the values are scalar and real. So long as the specified values pass those rudimentary checks, the values can be out of range for the RTL-SDR radio. In this case, the hardware makes its best effort to set the specified value and reports the actual value on the block mask.

Desired Versus Actual Value in Receiver System Object

The comm.SDRRTLReceiver System object™ properties display the specified values for the center frequency, sample rate, and frequency correction. However, due to quantization or range issues, the actual values can differ from your desired values.

For example, create a comm.SDRRTLReceiver System object, and then specify the center frequency.

h = comm.SDRRTLReciver
h.CenterFrequency = 1.03e9

Get the actual center frequency that is set at the RTL-SDR radio by using the info object function. The output r.CenterFrequency shows the actual center frequency.

r = info(h);
r.CenterFrequency

The System object sends the specified values to the RTL-SDR radio and then reads the actual values back when you use the info object function.