IWR6843ISK-ODS: RF output level

Takatoshi Tsuji

Expert 1550 points

Part Number: IWR6843ISK-ODS
Other Parts Discussed in Thread: IWR6843

Hello ,

According to datasheet of IWR6843, RF output level is typically +10dBm. But in my lab it actually seems +15 or +16 dBm.

I would like to know how to define(or measure) the output level in your lab.

Best regards,

Taka

over 5 years ago

0 Charles Oladimeji over 5 years ago

TI__Mastermind 33805 points

Hi,

The output power per TX is 10dB and the antenna gain is about 6dB. if you have 2 TX mode thats about 18dB.

you can use power backoff to limit the TX power

https://e2e.ti.com/support/sensors/f/1023/t/893506?IWR6843-How-can-I-use-TX-backoff-with-IWR6843-

Regards,

Charles O

0 Takatoshi Tsuji over 5 years ago in reply to Charles Oladimeji

Expert 1550 points

Hello Charles,

1. I believe chirp signal from TXx is not generated at the same time. I mean that TX1 and TX2 are off while TX3 chirp signal is ON. I am not sure why total output power is increased from 10dB to 18dB.

2. I would like to know how you are measuring the output level so that I would measure in the same way.

Best regards,

Taka

0 Charles Oladimeji over 5 years ago in reply to Takatoshi Tsuji

TI__Mastermind 33805 points

Hi,

Even if single TX its will still be around 15dB if you add the gain to the TX output power.

Please see certification test setup on how to take the measurements

Regards,

Charles O

0 Takatoshi Tsuji over 5 years ago in reply to Charles Oladimeji

Expert 1550 points

Hello Charles,

Excuse me for slow response.

According to Clause 7.2 Spectral power density, it is -7.31, -11.44 and -19.99dBm which has prenty of margin to spec(13dBm).

But I am not sure how you define your spec of output level(10dBm) from this result. Please kindly explain.

Best regards,

Taka

0 Charles Oladimeji over 5 years ago in reply to Takatoshi Tsuji

TI__Mastermind 33805 points

Hi Taka,

Please see section 7.3 of the report not the average power density.

Regards,

Charles O

0 Takatoshi Tsuji over 5 years ago in reply to Charles Oladimeji

Expert 1550 points

Hello Charles,

Results in section 7.3 is same as 7.2. Because there is different margin to limit(20dBm) among BW mode.

Please let me know how you define output level as RFIC.

Best regards,

Taka

0 Charles Oladimeji over 5 years ago in reply to Takatoshi Tsuji

TI__Mastermind 33805 points

Hi Taka,

It appears I misunderstood the question. Can you please explain what you mean by the question below?

Takatoshi Tsuji said:
But I am not sure how you define your spec of output level(10dBm) from this result. Please kindly explain.

Regards,

Charles O

0 Takatoshi Tsuji over 5 years ago in reply to Charles Oladimeji

Expert 1550 points

Hello Charles,

My issue is data correlation between my measurement result(15 or 16dBm) and your datasheet(10dBm).

Generally speaking, it is occurred due to difference of measurement condition.

But you are asking me to refer the test report for EU certification, where there are many results and then I am not sure which one should be referred.

Also, I may ask chirp configuration like output level and duty ratio when you suggest which one I should refer, so that I can compare our measurement condition to yours.

Best regards,

Taka

0 Charles Oladimeji over 5 years ago in reply to Takatoshi Tsuji

TI__Mastermind 33805 points

Taka,

Sorry for the delayed response, I was out on vacation.

The datasheet say 10dB because that is the output of the IC, If you measure TX power at the TX pin on the IC you will get 10dB. This does not include the antenna gain of the EVM. The EVM has antenna gain of ~7 dBi.

The examples in the lab does not include power back off so we are transmitting at full power, meaning TX power measured at boresight will be ~17dB

Regards,

Charles O

0 Takatoshi Tsuji over 5 years ago in reply to Charles Oladimeji

Expert 1550 points

Hello Charles,

Please kindly provide a document to understand the measurement method in your lab so that I can check measurement correlation.

- signal waveform : CW or chirp (in case of chirp, the parameter is needed.)

- equipment : spectrum analyzer ? how to make probing ?

Best regards,

Taka

0 Chloe Shay71 over 5 years ago

TI__Expert 4025 points

Hi Taka,

To measure the EIRP we radiate one TX at a time at full power and receive it with a horn antenna leading to a spectrum analyzer. You may need to use a down-converter to feed the spectrum analyzer at a lower frequency if your spectrum analyzer doesn't reach >62GHz. To calculate EIRP you need to account for the path loss, horn antenna gain, loss of the down-converter, etc. It is also very important to align the horn antenna well with the device.

Best,

Chloe

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IWR6843ISK-ODS: RF output level