Bandwidth is the value of the upper and lower range of the frequency occupied by the device, just like the antenna resonant frequency range mentioned above, or like the width of the road occupied by a car. Sometimes the bandwidth of the device is required not to exceed a certain value. To maximize the utilization of frequency resources, sometimes the bandwidth of the equipment is required to be wider to obtain better use effects.
Step refers to the rate and progress of frequency adjustment, or just like a person walking, the length of forward and backward steps. The step value is large and the adjustment speed is fast, but the accuracy is not enough and it is easy to miss the required steps. Frequency and step value are too small, which will affect the adjustment efficiency.
The threshold is the upper and lower limits, and changes will occur when the threshold is reached. My understanding is the threshold and limit.
My rough understanding is not very good. I hope it can help you.