Accuphase T-1200 - DDS FM Stereo Tuner

- Key Features
  
  Double-tuned front end: handles both very weak and very strong FM signals with excellent selectivity.
  
  Revolutionary DDS (Direct Digital Synthesis) local oscillator: boosts frequency purity and lowers noise.
  
  Variable bandwidth IF filter: allows switching between several bandwidths (50, 75, 100, 150, 250, 500 kHz) to reduce interference.
  
  Multipath Reduction (MPR): DSP-based suppression of signal reflections (multipath) for clearer reception.
  
  Digital FM demodulator: major IF and demodulation stages moved to high-speed DSP software for minimal distortion and noise.
  
  DS-DC stereo demodulation system: Accuphase’s original Direct Synthesis + Double Cancellation method for superb stereo separation.
  
  MDS-type D/A converter: dual-DAC per channel in parallel in a fully balanced output stage.
  
  20-station memory presets: quick access to broadcast stations along with stored tuning/IF settings.
  
  Balanced (XLR) and single-ended (RCA) analog outputs, plus a digital output (coaxial) for feeding external equipment.
  
  Remote control, pulse-tuning knob, signal/multipath meter display, and robust build quality.

Description

Using a blend of the latest RF circuit design with sophisticated digital signal processing, most major functions after the intermediate frequency stage, such as the variable bandwidth IF filter, multipath reduction, digital FM demodulator, and DS-DC stereo demodulation, have been moved to software on the DSP chip. Manual tuning using the pulse tuning method, plus 20-station memory tuning. A digital output provides further flexibility. Realizing impeccable sound quality and outstanding performance in an easy-to-use format, this FM tuner has been developed for demanding audio and music connoisseurs.

Warranty:

1-year manufacturer’s warranty

Features:

Double-tuned front end easily handles high signal levels
Revolutionary DDS principle for the local oscillator
Variable bandwidth IF filter prevents interference
Multipath reduction function
Digital FM demodulator keeps distortion and noise to a minimum
DS-DC achieves ideal stereo demodulation with DSP technology
MDS type D/A converter
Memory buttons give quick access to 20 stations

Benefits:

DDS FM stereo tuner “T-1200.”
The “T-1200” is the highest-class FM stereo tuner that is a full model change of the T-1100.
It was born by actively promoting the digitization of major components, such as the fusion of analog high-frequency technology cultivated over many years and advanced digital technology, and the adoption of high-speed operation type DSP.
The “T-1200” is a product that allows you to rediscover the charm of FM broadcasting and is the culmination of the AccuPhase, which has continued to develop FM tuners since its foundation.

“Two-stage double-tuned front end” with thorough measures against large input interference
In the front end of the FM tuner, only the desired station is selected from a large number of radio waves entered from the antenna, amplified by the RF amplifier, and then mixed with the high-frequency signal and the signal of the local oscillator (Local Oscillator), and the intermediate frequency ) is converted. It is natural to select weak radio waves as the role of the front end, but it is also important not to cause interference or distortion for broadcasting stations with a strong electric field strength, which is an absolute condition for high-quality reception.
The front end of this unit uses the LOCAL button on the front panel to switch the attenuator for the signal that first enters from the antenna according to the input level, and cope with excessive input when the area near the transmission tower or when using cable broadcasting.
This unit has a two-stage configuration in which a double-tuned circuit is installed before and after the high-frequency amplifier, and it has improved the interference wave elimination capability of the input to the mixer at the next stage, ensuring even better sensitivity and selectivity. The double-tuned circuit uses M (mutual induction) coupling. The high-frequency amplifier is equipped with a “dual-gate MOS FET” with excellent third-order intermodulation product characteristics, and AGC (Automatic Gain Control) is applied to operate it to obtain the best gain depending on the antenna input level. I will.

Achieving an astonishingly high SN ratio by incorporating the revolutionary DDS (Direct Digital Synthesis) in the local oscillator
This unit is equipped with a revolutionary DDS (Direct Digital Synthesis) as a local oscillator. Since the DDS does not use feedback, it can generate an output signal with the same frequency purity as a crystal oscillator circuit. Therefore, by using DDS, it is possible to realize a superheterodyne front end with a surprisingly high SN ratio without injecting unnecessary frequency modulation components into the received signal.
The original clock of 196.608MHz is used for the oscillator circuit of the master clock of DDS, and it contributes to the achievement of a high SN ratio. In addition, the output section achieved a remarkable spurious suppression by outputting a high-precision and low-distortion sine wave from the 786.432MHz/14-bit D/A converter.

Full digitalization of the intermediate frequency (IF) circuit and later
The intermediate frequency (IF) signal from the front end is digitized by the A/D converter, and the high-speed and high-precision DSP (Digital Signal Processor) is adapted from the <<variable IF band filter>> to <<stereo demodulator>>. We were able to dramatically improve full digital processing and performance/characteristics.
In addition, the excellent <<Multipath Reduction (MPR) function>> can significantly suppress the influence of interference waves due to reflections from buildings and mountains, resulting in high-quality demodulation and high-quality sound with less distortion and noise. Enabled voice output.