Philips 247E3LHSU/00, Service Manual

Page: 109 / 119

Meridian 3 109
Audio
3.17.1 Frequency Response
The amplifier and speaker combination shall provide a frequency response of 300 Hz to
20 kHz, with +/- 3 dB variation over the entire response range.
3.17.2 Total Harmonic Distortion
Total harmonic distortion shall be limited to 5% THD at the maximum wattage speaker
rating specified in section 1.3, at 1 kHz, when the input is 1.0Vrms.
3.17.3 Power Handling
Each speaker transducer shall accept up to the specified Wattage of audio power
without damage or exceeding the frequency response and total harmonic distortion
specifications.
3.17.4 Audio Amplifier
The amplifier shall provide two channels of audio up to 1.5 Watts per channel from 100
Hz to 20 kHz, based upon an audio signal input of 1.0V RMS per channel.
3.17.5 Volume Control
For monitors with a manual volume control, the direction (at the bottom) of the bezel
volume control is “-“ key for Minimum volume and “+” key for Maximum volume. The
default shipping position of the Volume Control shall be approximately 90%.
3.17.6 Speaker Sensitivity
The speakers shall support a minimum sensitivity of 75 dB +/- 3 dB at 2W/1m at 1 kHz.
3.17.7 Maximum Audio Card Output
The monitor audio amplifier shall accept a maximum input voltage of 1.5 Vrms and meet
the following requirements at the maximum monitor volume setting:
1. The ratings of the audio amplifier may not be exceeded.
2. The ratings of the speakers may not be exceeded.
3. There must not be any clipping of the audio amplifier output signal.
Voltage dividers may be used to reduce the input signal level.
3.17.8 Monitor Audio Amplifier Input Impedance
The monitor audio amplifier shall have minimum 10K Ohm AC input impedance
Power sensor (option)
UNCTIONAL Requirements for the front detection
For the presence sensor functionality, the following requirements are defined:
Two IRs be used for user present detections, one IR is for transmission signals, the other one is for receiving
reflection IR signals