Daewoo DTP-28B1, Service Manual

Page: 23 / 76

- 23 -
- high deviation FM-mono mode (max. deviation: approx. ±360 kHz)
4-2-1-2 DSP-Section (Audio Baseband Processing)
- flexible selection of audio sources to be processed
- performance of terrestrial de-emphasise systems (FM, NICAM)
- digitally performed FM-identification decoding and de-matrixing
- digital baseband processing: volume, bass, treble
- simple controlling of volume, bass, treble
4-2-1-3 Analogue Section
- two selectable analogue pairs of audio baseband input (= two SCART inputs) input level: <2 V RMS,
input impedance: >25
- one selectable analogue mono input (i.e. AM sound): Not used in this chassis
- two high-quality A/D converters, S/N-Ratio: >85 dB
- 20 Hz to 20 kHz bandwidth for SCART-to-SCART copy facilities
- loudspeaker: one pair of four-fold oversampled D/A converters. Output level per channel:
max. 1.4 VRMS output resistance: max. 5 . S/N-ratio: >85 dB at maximum volume Max.
noise voltage in mute mode: < 10 V (BW: 20 Hz... 16kHz)
- one pair of four-fold oversampled D/A converters supplying a pair of SCART-outputs.
output level per channel: max. 2 V RMS, output resistance: max. 0.5 , S/N-Ratio: >85 dB (20 Hz... 16 kHz)
4-2-1-4 NICAM plus FM/AM-Mono
According to the British, Scandinavian, Spanish, and French TV-standards, high-quality stereo sound is transmitted
digitally. The systems allow two high-quality digital sound channels to be added to the already existing
FM/AM-channel. The sound coding follows the format of the so-called Near Instantaneous Companding System
(NICAM 728). Transmission is performed using Differential Quadrature Phase Shift Keying (DQPSK. Table below
offers an overview of the modulation parameters.)
In the case of NICAM/FM (AM) mode, there are three different audio channels available: NICAM A, NICAM B, and
FM/AM-mono. NICAM A and B may belong either to a stereo or to a dual language transmission. Information about
operation mode and about the quality of the NICAM signal can be read by the controlling software via the control bus.
In the case of low quality (high bit error rate), the controlling software may decide to switch to the analogue FM/AM-
mono sound. Alternatively, an automatic NICAM-FM/AM switching may be applied.
4-2-1-5 German 2-Carrier System (DUAL FM System)
Since September 1981, stereo and dual sound programs have been transmitted in Germany using the 2-carrier system.
Sound transmission consists of the already existing first sound carrier and a second sound carrier additionally
containing an identification signal. More details of this standard are given in Tables below. For D/K very similar
system is used.