This new ”DDS FM Stereo tuner T-1200” is thesuccession model of T-1100 launched back in 2010.
Using a blend of Accuphase traditional RF circuit design
with sophisticated digital signal processing, ”Variablebandwidth IF filter”, “Multipath reduction”, “Digital FM
detector”, “DS-DC stereo demodulator” have been
moved to software on the DSP chip.
With further refinement of whole unit, the noise
performance or the stereo separation is impressively
improved than former model.
Discover supreme listening pleasure with this ultimate
tool of FM stereo broadcasts, which Accuphase has beendeveloping since the day of establishment.

1

Accuphase tidies up the gorgeous design which is worth
the sound quality and performance with new 10mm taller
front panel.

2Only the front end which selects and amplifies the weakradio signals is analog circuit. After the front end, allcircuits including local Oscillator are digital signalprocessing.
Digital signal processing section consists of 2 pcs of DSP.
40bit floating- point processor ADSP-21369(AnalogDevices) is used as 1st DSP, and it performs “Variablebandwidth IF filter”, “Multipath reduction”, “Digital FMdemodulator”.
2nd DSP is TMS320F2810(TI), and it is used as a ”DSDC stereo demodulator”.

3The front end in FM tuner just picks out and amplifies thedesired station signal from many others coming from theantenna, and converts it to the intermediate frequency.
It is very important section to decide the characteristics likereceiving sensitivity or selectivity.
・RF attenuator
It works to handle the broadcast stations with strong
electric
intensity while suppressing interference or crossmodulation.
・Two-stage double-tuned turning circuit
It achieves both excellent selectivity and low crossmodulation distortion.
・Automatic Gain Control
It optimizes the RF Amplifier gain according to antenna
inputlevel.
・Double Super heterodyne
With 2 step frequencies conversion, it blocks the4

interference
signal and optimally converts the frequencies for the A/D
converter at next stage.

4

Generally, PLL(Phase Locked Loop) circuit is used for a
local oscillator. In a conventional PLL circuit, feedback isused to stabilize the frequency, but this produces
frequency modulation components that tend to degrade
tuner’s noise characteristics.
The local oscillator in the T-1200 is a DDS(Direct DigitalSynthesis) circuit.
With DDS, the output of a quartz oscillator is divided toadjust the timing that governs the readout of data, andcreate the sine wave. There is no feedback loop, thefrequency purity of the quartz oscillator is maintained as
it is until the output.
T-1200’s outstanding low noise characteristic is createdby this revolutionary circuit.

5

Variable bandwidth IF filter reduces the influence of noiseor neighbor station’s signal.
It allows the user to obtain a good quality signal from astation affected by interference from a strong adjacentstation.
The variable bandwidth IF filter is implemented using aFIR(Finite Impulse Response) type digital filter withcomplete linear phase characteristics, thereby
eliminating the phase shift that can occur withconventional IF filter.

6

Multipath reception refers to a condition where the samebroadcast signal reaches the antenna via several
different propagation routes.
When the direct wave and reflected waves are received
together, distortion and noise occur.
MPR(Multipath Reduction) is an innovative technologythat effectively suppresses the harmful reflected waves,resulting in high-quality audio output without multipath.

7

MPR applies the adaptive filter technology thattransforms the filter shape to minimize multipath.
MPR function is based on high-speed, high-precision
signal processing by 40bit floating point DSP chip.

8

FM demodulator circuit is also based on 40bit floating
point DSP chip precisely calculating the theoreticalformula to demodulate the FM signal.
Therefore, it enables the ideal FM demodulation with nodistortion and noise.

9DS-DC is an Accuphase original stereo demodulationtechnology which achieves amazing stereo separation.
DS-DC comprises the two technologies described below.
・Pilot Tone Direct Synthesis
With DS-DC, 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 evenwhen a high level of noise is present.
Impressive stereo separation can be achieved evenwhen the pilot tone level is low.
・Crosstalk Double Cancellation
After the input signal has been separated into the left
and right components, the circuit eliminates crosstalkusing a dual approach that also takes phase shift intoconsideration.
The result is extremely thorough left/right separation.

10

For D/A converter section, Accuphase updates the DAC
chip to Asahi Kasei Micro Electronics’ Premium DAC
AK4490EQ for T-1200.
The former model T-1100 is equipped with
AD1955(Analog Devices).
AK4490EQ has 2 DACs inside, and T-1200 contains 2DACs connected in parallel per channel withAccuphase’s unique technology, MDS (Multiple DeltaSigma) conversion system.
And also fully-balanced structure “Direct Balanced Filter”
is employed after D/A converter in T-1200.

11Ultra Low Noise is one of the main technical features ofT-1200.
The former model, T-1100 has the excellent noise
performance, however, T-1200 achieves 20% lower
output noise voltage than T-1100.
T-1200 guarantees 92dB Signal to Noise ratio whichmeans 25.1μV of output noise voltage.

12

T-1200 proudly shows the great stereo separation
characteristics which are quite important for the quality ofmusic playback.
Though the guaranteed stereo separation is 65dB
@1kHz, actual value reaches to 80dB.

13

Accuphase original pulse tuning system provides
traditional manual tuning feel.
T-1200 is equipped with a digital output connector tooutput the high-quality broadcasts before D/A conversion.

14