IWR1642: for IWR1642, the max sampling frequency is 6.25Msps or 12.5Msps?

wang york

Intellectual 715 points

Part Number: IWR1642

for IWR1642, the max sampling frequency is 6.25Msps or 12.5Msps?

If only 6.25Msps is allowed, the complex 2x mode will have a half beat frequency.

is that right?

over 7 years ago

0 Charles Oladimeji over 7 years ago

TI__Mastermind 33805 points

Hi,

The max complex sampling frequency for the IWR1642 is 6.25 Msps, the max real sampling rate is 12.5 Msps.

See explanation about beat frequency in related post below

https://e2e.ti.com/support/sensor/mmwave_sensors/f/1023/t/613071?IWR1443-IWR1443-ADC-sample-rate-and-A2D-sample-rate-question-transmitter-gain

https://e2e.ti.com/support/sensor/mmwave_sensors/f/1023/t/595667?IWR1443-ADC-format-Complex-1x-vs-Complex-2x

Regards,

Charles O

0 wang york over 7 years ago in reply to Charles Oladimeji

Intellectual 715 points

OK, a further question,
if ADC is set complex 2x mode, does it mean only 3.125M is used for range detection, and the other 3.125M for interference detection?

0 Radio-Joe over 7 years ago in reply to wang york

TI__Mastermind 37500 points

Hello,
Yes with Complex 2x mode, (-3.125 to 3.125) the negative frequency -3.125 to 0 is used for interference detection, the 0 to 3.125Mhz is for range.
In Complex 1x mode, this is shifted (0 to 6.25), so the range can cover 0 to 6.25.

One other component the DFE decimation filtering is 80% passband, so the max passband beat frequency is lower.

Regards,
Joe Quintal

0 Radio-Joe over 7 years ago

TI__Mastermind 37500 points

Hello,

Yes, for Complex 2x, with a 6.25Msps rate we have -3.125 to 3.125 range.

for Complex 1x, with a 6.25Msps rate we have a shifted frequency 0 to 6.25 range.

for real sampling with a 12.5Msps rate we have a 1st Nyquist zone of 0 to 6.25 range

Regards,

Joe Quintal

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IWR1642: for IWR1642, the max sampling frequency is 6.25Msps or 12.5Msps?