Acer A221HQV Acer A221HQV LCD Monitor Service Guide - Page 6

4 ACER A211H/A221HQ Go to contents page 1. Product Specification (continued) 1.3.2 Input Signals: 1.3.2.1 Video Signal Amplitudes: The video inputs consist of Red, Green and Blue signals each has its own coaxial cable terminated at the monitor. These video signals are analog levels, where 0V corresponds to black, and 700mV is the maximum signal amplitude for the respective color. The video signal is terminated with 75 ohms. 1.3.2.2 Video Signal Termination Impedance: The analog video signal termination shall be 75 ohm +/- 2%. 1.3.2.3 Synchronization (Sync) Signals: The Horizontal Sync (HS) TTL signal is used to initiate the display of a horizontal line. HS may be either active high or active low according to the timing. The Vertical Sync (VS) TTL signal is used to initiate the display of a new frame. VS may be either active high or active low according to the timing. 1.3.2.4 Sync Signal Levels: The monitor must accept sync signals from both 3.3 and 5 volt TTL logic families. The inputs shall sense a logic 0 when the input is 0.8 volt or less and shall sense a logic 1 when the input is 2.0 volts or greater. In addition to these level requirements, there shall also be a minimum of 0.3 volt hysteresis provided for noise immunity (typically by using a Schmitt Trigger input). That is, the input level at which the monitor actually detects a logic 0 shall be at least 0.3 volt lower than the level at which it actually detects a logic 1. If the monitor sync processing circuits were designed with 3.3 volt logic family, then the sync inputs must be 5 volt tolerant. 1.3.2.5 Sync Signal Loading: TTL input loading shall be equivalent to one TTL input load. When logic 0 is asserted by a sync input, the maximum current source from any single monitor sync input to the driver is 1.6 mA. When logic 1 is asserted, the maximum current source from the driver to any single monitor sync input is 400 uA. 1.3.2.6 Abnormal Signal Immunity: The monitor shall not be damaged by improper sync timing, pulse duration, absence of sync, abnormal input signal amplitude, or any other anomalous behavior of a graphics card. 1.3.2.7 Digital TMDS Input (DVI and HDMI signal input): These video inputs consist of TX0+/- to TX2+/-± and CLK+/- signals, each with its own shielded twisted pair. These video signals are digital levels. Each signal pair is terminated by a normal 100 ohms. 1.3.2.8 Audio Function (optional): This monitor integrated with stereo audio. Speakers: 2 x 1W Amplifier: Output 1W with 500mVrms Sine wave input. Input impedance: >22K Ohms. THD: