SampleRate drops when reading 4 channels at the same time

The details are shown below.

I input 1K sine signal to channel 1.

When I only read the data of ch1 and set the samples to 15000, which is 1ms period(1KHz) corresponds to the sample rate of 15MHz, I got 1 cycle of sine.

But if I added the acqurring channels, the frequency dropped down.

How can I keep the sample rate when reading multiple channels at the same time? 15000 samples vs 1ms period data.

Thank you!

Hi,

We will contact the product owner and get back to you.

Thanks,
Janine

Hi Liz,

Please see our team's response below.

When using IIOscope or Python to log data from all four ADC channels simultaneously, the sampling frequency is applied uniformly to all channels. As a result, the data is logged at 3.75MHz when all four channels are enabled. The uniform sampling frequency across all ADCs is consistent with the Linux kernel attribute definition (from Linux Documentation): 

What: /sys/bus/iio/devices/iio:deviceX/in_voltageX_sampling_frequency
Description:
Some devices have separate controls of sampling frequency for individual channels. If multiple channels are enabled in a scan, then the sampling_frequency of the scan may be computed from the per channel sampling frequencies.

Currently, there is no way to modify IIOscope or Python to simultaneously log multiple ADC channels at 15MHz. One way to view multiple DAC outputs at the full 15MHz would be connecting them to an external measuring device like an oscilloscope.

Thanks,

Xiaomeng

Instrumentation System Solutions

Hi Xiaomeng,

       Thank you so much for your response.