ONKYO Integra T-405
¥ 45,000 (around 1977)
Commentary
An FM/AM tuner equipped with servo lock and pursuing the concept of TQ = total quality.
Servo lock using high gain operational amplifier IC is adopted for the lock mechanism.
This realizes excellent locking accuracy within ± 5 khz of the best sound quality point, and quick and accurate channel selection by instantaneously locking to the optimum tuning point.
In the front-end section, a dual-gate MOS FET known for its low noise figure and wide dynamic range is inserted into the RF stage, and a frequency linear type four variable capacitor is adopted.
The IF section uses a wide-band linear phase filter strictly selected by the differential gain direct-viewing method, and the IF amplifier uses a differential IC to obtain a sufficient limiter effect.
In addition, the detector has also obtained wide-band linear characteristics by the differential gain direct-viewing method.
The MPX section is equipped with a high-stability AF amplifier, a new-type PLL and an IC to obtain an excellent stereo signal.
In addition, in order to suppress the generation of slight distortion, we have added a strengthening filter to the stable PLL / IC to ensure the low distortion factor of the MPX system as a whole.
In addition to the IF section and low-distortion MPX section of the wide-band linear phase filter, we have adopted an AF amplifier with a large dynamic margin to take thorough measures against overmodulation.
Equipped with 50% modulation 440 Hz continuous sound air check calibrator, low distortion rate recording is possible by setting an appropriate recording level.
By detecting the signal to the signal meter from three differential type limiters and using an IC that does not saturate even at a strong input, linear response characteristics up to a strong input of 70 dB realized.
The AM tuner section uses a highly sensitive double varicon and a highly selective IF triple tune filter to improve sound quality.
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Model Rating
| Type | FM/AM Tuner | ||
| FM Tuner Section | |||
| Receiving frequency | 76 MHz to 90 MHz | ||
| Practical sensitivity | 1.8 μ V (IHF, 300 Ω) 10.3 dBf (new IHF) |
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| S/N50dB sensitivity (IHF) | 3.0 μ V 14.8dBf |
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| Image interference ratio | 80dB(83MHz) | ||
| IF interference ratio | 95dB(83MHz) | ||
| Signal-to-noise ratio | mono:77dB stereo:73dB |
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| Spurious interference ratio | 90dB | ||
| 2-signal selectivity (± 400 kHz detuning) | 60dB | ||
| AM suppression ratio | 53dB | ||
| Capture ratio | 1.2dB | ||
| Distortion factor |
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| Frequency characteristic | 20 Hz ~ 15000 Hz + 0.5 -1.5 dB | ||
| Antenna impedance | 75 Ω, 300 Ω | ||
| Stereo separation |
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| Carrier leak | -60dB | ||
| Output voltage (400 Hz, 100% modulation) | 0 ~ 750 mv | ||
| Output impedance | 8k Ω (Maximum Variable Output) | ||
| Lock Collection Factor | 0.05 or less | ||
| Lock offset error | Within ± 5 khz | ||
| <AM Tuner Section> | |||
| Receiving frequency | 535 kHz to 1605 kHz | ||
| Practical sensitivity | 200 μ V/m (bar antenna) | ||
| Image interference ratio | 52dB(1MHz) | ||
| IF interference ratio | 38dB(1MHz) | ||
| Signal-to-noise ratio | 60dB | ||
| Distortion factor | 0.5%(400Hz) | ||
| Output Voltage (400 Hz, 30% Modulation) | 0 ~ 240 mv | ||
| <General> | |||
| Semiconductor used | Transistor : 17 FET : 1 IC : 3 Diode : 19 units |
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| Pwer | 100 VAC, 50/60Hz | ||
| Power consumption | 12W (Electrical Appliance and Material Control Law Standard) | ||
| External dimensions | Width 438x Height 150x Depth 392 mm | ||
| Weight | 6.5kg | ||