| 摘要 |
A constant current source supplies a bias current through a diode chain, establishing a first voltage at a terminal coupled to the string. A DC restorer circuit, responsive to a source of composite video signals, couples an additional current through the diode chain during the sync interval. This additional current establishes a second voltage level at the terminal. The second voltage is compared with a reference voltage for producing output signals synchronized with the sync pulses.
|
