PyQt4 : Sync between QSpinbox and QSlider

Question

I make a relation between QSpinbox and QSlider.
QSpinbox has a range -10.0 to 10.0, and QSlider has a range -100 to 100.
So, the value of QSlider divided by 10 is connect to QSpinbox, and vice versa.
I use "valueChanged()" SIGNAL to each other.
And I want to type "3.5" in QSpinbox, in this case when I type just "3", QSpinbox's "valueChanged" change QSlider's value, and QSlider do again. So, QSpinbox lose it's focus.
I can't type "3.5" in one shot.
"valueChanged()" SIGNAL works too diligently :)
How can I solve this issue?