Multipath doppler shift measurement

[saw86]

Hello everyone

I have single input single output network. I need to measure multipath and doppler shift measurement. Could anyone please help me how to measure those meaasurement. What is the proper measurement devices to measure multipath and doppler shift.

Thanks in advancce

 

[D.A.(Tony)Stewart]

First explain that you understand what it is.

Multipath fading such as Rice fading is when the signal reflects off a surface to arrive at a point where it cancels. It may drop up 40 dB+ from matched amplitudes and 180 deg phase or shifted by half wavelength path multiple at a given f.

Diversity antenna switching mitigates this.

Doppler is the moving phase drift or frequency shift from a relative motion between Tx and Rx. Tracking PLL mitigates this.

 

[vfone]

You need a Channel Emulator:

https://www.spirent.com/~/media/Datasheets/Mobile/SR5500_Data_Sheet.pdf

Unfortunately those devices are very expensive.

 

[jiripolivka]

Multipath generates a delay spread of received signal. Doppler generates a frequency shift due to movement of the TX or RX.
To measure you can use some expensive instruments.
To measure the delay spread, you can use a switched delay line in the reference channel.
To measure Doppler shift, you can use a discriminator in the receiver.

Details depend on carrier frequency and other link parameters.

 

[D.A.(Tony)Stewart]

It is easy to simulate fading in a shield room with standing waves.

Maybe a spin table with the mobile to do both Doppler and fading tests inside a shielded room will do both.