I am trying to set up the Urukul with an external low noise 1 GHz clock. The output frequency is correct, but there are other frequencies jumping around. I can see the 1 GHz leaking, the expected 100 MHz output, but also other frequencies, which are changing quicker than the refresh rate of the spectrum analyzer. I tried -5 dBm and 5 dBm for the clock.
I'm not sure if I configured everything correctly:
The flash configuration is set to:
{
"type": "urukul",
"hw_rev": "v1.5.2",
"ports": [
5,
6
],
"synchronization": true,
"clk_sel": 1,
"pll_en": 0,
"refclk": 1e9,
"clk_div": 1
}
In the (generated) device_db I added/changed:
device_db["urukul0_cpld"] = {
"type": "local",
"module": "artiq.coredevice.urukul",
"class": "CPLD",
"arguments": {
"spi_device": "spi_urukul0",
"sync_device": "ttl_urukul0_sync",
"io_update_device": "ttl_urukul0_io_update",
"refclk": 1e9,
"clk_sel": 1,
"clk_div": 1
}
}
And for all DDS channels on that Urukul:
device_db["urukul0_ch0"] = {
"type": "local",
"module": "artiq.coredevice.ad9910",
"class": "AD9910",
"arguments": {
"pll_en": 0,
"chip_select": 4,
"cpld_device": "urukul0_cpld",
"sw_device": "ttl_urukul0_sw0",
"sync_delay_seed": "eeprom_urukul0:64",
"io_update_delay": "eeprom_urukul0:64"
}
}
The script used:
from artiq.experiment import *
import numpy as np
from artiq.coredevice.ad9910 import _AD9910_REG_FTW
class DDSTest(EnvExperiment):
def build(self):
self.setattr_device("core")
self.setattr_device("urukul0_cpld")
self.setattr_device("urukul0_ch0")
def run(self):
self.initialize()
self.set_values()
@kernel
def initialize(self):
self.core.break_realtime()
self.urukul0_cpld.init()
self.urukul0_ch0.init()
@kernel
def set_values(self):
self.core.break_realtime()
delay(100*us)
self.urukul0_ch0.set(100e6)
self.urukul0_ch0.sw.on()