Audio Database

Image of the Integra T-429
Commentary

FM stereo tuner using FM feedback system and W super servo system.

In the FM feedback system, part of the output signal of the detector is fed back to the local transmitter through the FM servo circuit, and the local transmitter signal is modulated by the low distortion circuit built into the local transmitter. The modulated local transmitter signal is mixed with the input signal by a mixer and an IF signal is extracted.
Therefore, the FM feedback method has the same effect as doubling the bandwidth of the IF circuit and allows only the part of the IF circuit with the best phase characteristics to pass through.
As a result, the dynamic range of the IF circuit is expanded, and a low distortion factor can be maintained even in the wide IF signal band accompanied by large input in overmodulation.
In addition, since it has the NFB effect, linearity in the IF and detection section is greatly improved, and distortion can be reduced.
Other features include improved separation at the MPX by clearing the signal, enhanced effect of the servo lock system by widening the IF band, and improved tuning accuracy.

Even if a slight phase shift occurs in the detector output signal, the FM servo does not work.
Therefore, since it is necessary to obtain excellent phase characteristics, the IF linear phase filter and wideband ultralinear detector are strictly selected and adopted.
In addition, it is equipped with 2-stage switching of IF bandwidth (low distortion rate WIDE, high selectivity NARROW), and FM feedback is operated only when WIDE.

The front end consists of a direct-input triple-chain frequency linear 7-train varicon and a wide dynamic range dual-gate MOS FETx2 double balanced mixer.
The output from the station is fed into the mixer through a tuned buffer consisting of a 3-terminal MOS FET, thereby eliminating intermodulation interference ratio and intermodulation interference.

The antenna input stage is two stage switching between Booster Out (direct) and Booster In. The sensitivity can be selected according to the receiving condition.
The Booster Out is a position that can show performance in a strong electric field region. After the input triple tune, it enters directly into the mixer without going through RF (harmonic amplification). By ensuring a sufficient dynamic range, interference such as intermodulation is eliminated, and stable and clear reception is possible.
Also, the Booster In is a position for the weak electric field region, and before the triple tune, there is RF2-stage amplification (input single tuning) by MOS FET.
This makes it possible to receive weak radio waves from a long distance.

In the MPX section, a high-speed response C-MOS analog switching element is used for the switching element, and an active filter and a pilot canceler are used to cut the sub-carrier component after L/R separation to prevent sound quality degradation caused by magnetic distortion of the LC low-pass filter.

All circuits after MPX are equipped with double super servo amplifier which is the amplifier technology of ONKYO.
In this method, the + and - terminals of the tuner output feed back to the MPX input only the harmful noise and distortion components generated in the output and cancel the feedback. At the same time, the distortion due to the slight impedance of the ground line inside the tuner is suppressed.

It uses a touch sensor circuit that cuts low-frequency pop noise only when the tuning knob is touched.

Uses a touch sensor servo lock system for comfortable channel selection and perfect synchronization.

Equipped with 440 Hz air check and calibrator.

Equipped with automatic noise reduction.

Equipped with a deviation meter with multipath detection useful for antenna installation.

Model Rating
Type FM Feedback System W Super Servo FM Stereo Tuner
FM Tuner Section
Receiving frequency 76 MHz to 90 MHz
Practical Sensitivity (75 Ω / IHF) RF Booster out : 1.75 μ V/16.1 dBf
RF Booster in : 0.9 μ V/10.3 dBf
S/N50dB sensitivity (75 Ω / IHF) RF Booster in : 1.7 μ V/15.8 dBf
Intermodulation interference ratio
(± 1 mhz / ± 2.5 mhz)
RF Booster out:100dB/105dB
RF Booster in:90dB/100dB
Image Interference Ratio (83 mhz) RF Booster out:100dB
RF Booster in:120dB
IF Interference Ratio (83 MHz) RF Booster out:110dB
RF Booster in:120dB
Signal-to-noise ratio mono:90dB
stereo:86dB
Spurious interference ratio RF Booster out:100dB
RF Booster in:120dB
2-signal selectivity (± 400 kHz detuning) IF Wide:45dB
IF Narrow:85dB
AM suppression ratio IF Wide:65dB
IF Narrow:55dB
Capture ratio IF Wide:1.0dB
IF Narrow:2.0dB
Distortion factor
Mono, 50 Hz to 10 kHz : 0.04%(IF Wide)
0.15%(IF Narrow)
Stereo, 400 Hz : 0.02%(IF Wide)
0.3%(IF Narrow)
Stereo, 50 Hz to 10 kHz : 0.08%(IF Wide)
0.4%(IF Narrow)
Frequency characteristic 2 Hz ~ 15000 Hz + 0.2 -0.8 dB
Antenna impedance 75 Ω
Stereo separation
1kHz: 60dB(IF Wide)
45dB(IF Narrow)
100 Hz to 10 kHz : 50dB(IF Wide)
40dB(IF Narrow)
Carrier leak -65dB
Output Voltage / Impedance Variable Output : 0 ~ 1200mV/1k Ω
Fixed Output : 450mV/3.3k Ω
<General>
Pwer 100 VAC, 50/60Hz
Power consumption (Electrical Appliance and Material Control Law standard) 28W
External dimensions Width 435x Height 99x Depth 393 mm
Weight 7kg
Sold Separately Sidewood CW-9 (¥ 5,000)