Response in dB
Frequency in Hz
Stereo Separation
#HANNEL
3EPARATOR
#ROSSTALK
$OUBLE#ANCELLATION
Pilot Tone
Stereo-Modulated
Signal
#ROSSTALK
#ANCELLATION
（
STSTAGE
）
,
2
#ROSSTALK
#ANCELLATION
（
NDSTAGE
）
0ILOT4ONE
$IRECT
3YNTHESIS
20 30 50 100 200 500 1k 2k 3k 5k 10k
0
−10
−20
−30
−40
−50
−60
−70
−80
−5
−15
−25
−35
−45
−55
−65
−75
Lch
→
Rch
Rch
→
Lch
Stereo Separation Characteristics
■
DS-DC Type Stereo Demodulator Circuit
■
Intermediate frequency (IF) signal from
front end is digitized by high-precision
A/D
converter
■
Functions after intermediate frequency (IF) stage (variable
bandwidth IF filter, multipath reduction, digital FM
detector, DS-DC stereo demodulator) are performed
through fully digital signal processing b
y a h i g h - s p e e d ,
h i g h - a c c u r a c y D S P c h i p , p r o v i d i n g d r a s t i c a l l y i m p r o v e d
performance. The end result is an FM tuner of the highest
order.
■
Supplied Remote Commander RC-410
Provides access to all functions of the tuner
(except power switching), as well as
(Accuphase) amplifier volume control.
●
DS-DC (Direct Synthesis
−
Double Cancellation)
/
Pilot Tone Direct Synthesis
A conventional FM tuner uses a PLL circuit to extract the pilot tone and obtain the
frequency and phase components from the input signal (stereo-modulated signal). If the
level of the pilot tone decreases, noise will be heard and stereo separation becomes
extremely poor.
With DS-DC, the waveform of the pilot tone in the input signal is identified as is* and
generated directly by the DSP arithmetic. Therefore the pilot tone can be extracted
reliably even when a high level of noise is present. Impressive stereo separation can be
achieved even when the pilot tone level is low.
※
Simply analyzing the signal and determining similarities.
4
Crosstalk Double Cancellation
After the input signal has been separated into the left and right components, the circuit
eliminates crosstalk using a dual approach that also takes phase components into
consideration. The result is extremely thorough left/right separation.
DS-DC principle with DSP ensures ideal stereo
demodulation for amazing channel separation
The stereo demodulator in the T-1100 features
another Accuphase innovation called DS-DC (Direct
Synthesis
−
Double Cancellation). The demodulator
comprises the two technologies described below.
Since all operations are carried out through software-
based algorithms in Digital Signal Processor, ideal
demodulation performance can be achieved, result-
ing in previously unheard-of channel separation.
