AWR1243BOOST: AWR1243BOOST

What happens if the transmitter signal is not mixed with the receiver signals?

I received this response from Vivek Dham

Vivek Dham replied to AWR1243BOOST: Application for biomedical research project.

Hello Don,

Both AWR1243 and IWR6843 devices can be configured to receive only by not turning ON any Tx in the chirp configuration  API.

Regards,

Vivek

You are indicating that the system cannot operate without the transmitter being on but the above answer I got from Vivek indicates that the receiver can be operated without the transmitter being on.  Which one of you are correct?

Hello Don,

What Cesar meant was for the regular FMCW radar operation you need both the TX and Rx of the same device operational. But for what ever reason you just want to use the Rx only the device allows to do so by keeping the Tx disabled. But please note that in that case the down converted signal on the Rx side will be based on what ever signal is present at the Rx input and there will be no synchronization between that signal and the AWR device Rx.

regards,

Vivek

I am not sure what is meant by "no synchronization between that signal and the AWR device Rx".  This answer would indicate that the output is not synchronized to the input.  I do not know how than can be since the only difference between the input and the output is the local oscillator. All I want is to be able to amplify the input, down convert by the local oscillator and have an output that represents that function.   Please explain. Thank you

Hello Don,

In a typical FMCW application the local oscillator is enabled ramped according to the programmed timing (chirp and frame timing) and the signal is sent over the TX , the Rx is synchronized to the same timing to start the sampling also accordingly. When you use the external signal and no the internal Tx to generate the signal this timing synchronization would inherently not be available.  

regards,

vivek

Also the reference frequency of the AWR device and the external source may not be synced, so there could be a frequency difference between the two.

regards,
Vivek

Hello Don,

Like I said there is a test mode in AWR1243 where you can operate the LO in fixed frequency. From what I understood this is what you wanted.

Regarding the clock frequency error between the AWR device and your input source, this cannot be resolved at device level. If two separate clock sources are used for two devices there can always be a frequency error. I do not have information about your external signa source, but if you can  use a common reference clock for both the devices then you can overcome the frequency error difference. Also I am not sure if the frequency difference impacts your application, if it does not then you don't have to worry about it.

regards,

Vivek