connect(&_device_selector, SIGNAL(currentIndexChanged (int)),
this, SLOT(on_device_selected()));
_sample_rate_value.setDecimals(0);
_sample_rate_value.setSuffix("Hz");
connect(&_device_selector, SIGNAL(currentIndexChanged (int)),
this, SLOT(on_device_selected()));
_sample_rate_value.setDecimals(0);
_sample_rate_value.setSuffix("Hz");