How to achieve 2MHz bandwidth for FCC unmodulated test using radio_test

Question

Our compliance engineers are failing the unmodulated FCC test for our radio because the signal only spans 1MHz, but needs to span 2MHz. We do not have this issue when using the modulated signal. We are using the radio_test example to perform these FCC tests. 
 What modifications can be made to the radio_test example to achieve the required bandwidth? 
 Regards, Drew

Andreas · Accepted Answer

Hi Drew, 
 
 Not quite sure what you are testing against here, in which clause is this a requirement? Normally 6dB bandwidth is against a >500kHz requirement, to pass this you need to use the 1Mbps BLE mode (not 1Mbps NRF mode). If you are using an older SDK (v15.0 or earlier) this by default uses NRF mode, you need to change that in the source or use a newer version. The 1Mbps BLE mode also has a ~1MHz 99% bandwidth, to increase to 2MHz you need to use 2Mbps BLE mode. 
 Still, this is only with a modulated carrier, an unmodulated carrier is just a tone with BW << 1MHz. 
 
 Best regards, 
 Andreas

How to achieve 2MHz bandwidth for FCC unmodulated test using radio_test

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