Exposure Control and Synchronous Scanning
Non-industrial grade cameras do not support the asynchronous reset feature. This means that the frame readout condition repeats itself periodically at some permanent frequency called the "frame rate". This is called the synchronous scanning mode.
This does not preclude some exposure control capability. Most synchronous cameras make possible to overlap the exposure and readout conditions. This feature is often referred to as "electronic shutter".
In the following figure, the exposure condition before a given transfer gate is responsible for the building of a video image which is extracted out of the camera during the readout condition that follows this transfer gate.
Exposure control and synchronous scanning
The depicted cycling repeats indefinitely.