SONY DNW-A28P
Service Manual

(2) Audio Signal Processing Block (CP-344, AU-249, SDI-23, APR-27A, and HP100 Boards)
The analog audio signal input from the external equipment to the AUDIO IN connector (on the CP-344 board) is switched in an input level on the CP-344 board and controlled in a level. The resultant signal is sent to the AU-249 board. On the CP-344 board, phantom power is also supplied. An automatic gain control (AGC) is applied to the audio signal sent to the AU-249 board. This audio signal and the Dolby noise-reduced analog Betacam PB audio signal are switched and emphasized. The resultant signal is converted from analog to digital and sent to the APR-27A board. For the SDI signal input from the external equipment to the SDI In connector, an audio signal and various control signals (mute flag, Z flag, and C bit signals) are extracted on the SDI-23 board and sent to the APR-27A board. On the APR-27A board, five-field sequence processing (for NTSC only) and JOG processing are performed for the SX PB audio signal sent from the DPR-87 board. This SX PB audio signal, the analog input signal sent from the AU-249 board, and the SDI input signal sent from the SDI-23 board are switched, swap in channels, mixed in channels, and muted. These signals are then sent to the boards below. REC signal: To the DPR-87 board LINE and MONITOR output signals: To the AU-249 board SDI output signal: To the SDI-23 board The LINE output signal sent to the AU-249 board is converted from digital to analog and de-emphasized. The signal is then output through the output amplifier on the CP-344 board from the connector panel. The MONITOR output signal sent to the AU-249 board is converted from digital to analog and deemphasized. The output signal is then gain-controlled on the HP-100 board and output through the output amplifier on the CP-344 board from the connector panel. The MONITOR output signal can also be monitored using headphones or speaker. The channel type of the signal to be output to the LINE and MONITOR output connectors can be set using a sub menu. The output audio signal sent to the SDI-23 board is multiplexed with a video signal using an SDI encoder, converted from parallel to serial, and output from the connector panel.

3-4 (E)

DNW-A28 DNW-A28P