TRIO KT-990
¥ 53,800 (released in 1982)
Commentary
An FM/AM tuner developed with the theme of high SN ratio and low distortion rate in order to respond to the era of digital audio sources for FM stations.
We have adopted a double-convert pulse count method to support digital source conversion. We have improved the SN ratio and distortion factor by a method composed of two ICs double-convert to obtain a high SN ratio by lowering only the FM carrier signal without modifying the modulation signal, and pulse count with less distortion over a wide band for linear detection.
The front end consists of dual gate MOS FET and high-precision F 4 series variable capacitor, single and double.
A newly designed clean reception filter is used in the IF section to suppress 38 kHz harmonics such as 114 kHz and 190 kHz, which are especially easy to hear, and to reflect the good quality of data in the sense of hearing.
The MPX section employs a PLL system, especially a chopper type demodulation circuit, to achieve low distortion and high SN.
In addition, 19 kHz and 38 kHz canceller circuits have been installed to achieve a 56 dB suppression ratio.
The AM part adopts IF2-stage switching.
In the WIDE position, AM broadcasting is transmitted flatly up to 15 kHz. In order to receive high quality AM broadcasting, flat frequency characteristics are realized over a wide band.
In addition, the NARROW position has almost the opposite frequency characteristics to the pre-emphasis characteristics of general broadcasting stations, and flattens the frequency characteristics of superemotions.
Equipped with a touch servo lock mechanism that selects the tuning point with the tuning knob and sets it to the accurate tuning point when the hand is released.
In addition, in order to make it easier to visually pick up the tuning, a 2-color 7-point signal LED and a 3-color 2-point tuning LED are used. The signal meter lights red when it approaches the tuning point and turns green at the tuning point.
The tuning LED is red to indicate the time of detuning. When the tuning LED approaches the tuning point, only one side turns orange and both sides turn orange to indicate the perfect tuning point.
Model Rating
| Type | FM/AM Tuner | ||||||||||||||||||||||||||||||
| FM Tuner Section | |||||||||||||||||||||||||||||||
| Receiving frequency range | 76 MHz to 90 MHz | ||||||||||||||||||||||||||||||
| Antenna impedance | 75 Ω unbalance | ||||||||||||||||||||||||||||||
| Sensitivity (75 Ω) | 0.95 μ V (IHF), 10.8 dBf (new IHF) | ||||||||||||||||||||||||||||||
| SN ratio 50 dB sensitivity | Mono : 1.8 μ V (IHF), 16.4 dBf (new IHF) Stereo : 20 μ V (IHF), 37.3 dBf (new IHF) |
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| Harmonic distortion factor (100% modulation) |
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| SN ratio (100% modulation, 85 dBf input) | mono:90dB stereo:83dB |
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| Capture ratio | Wide:1.0dB Narrow:2.0dB |
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| Effective selectivity | Wide:45dB Narrow : 65 dB (± 300 kHz) |
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| Stereo separation |
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| Frequency characteristic | 20 Hz to 15 kHz ± 0.5 dB | ||||||||||||||||||||||||||||||
| Image interference ratio (84 MHz) | 90dB | ||||||||||||||||||||||||||||||
| IF / Spurious Interference Ratio (84 MHz) | 100dB/120dB | ||||||||||||||||||||||||||||||
| AM suppression ratio / subcarrier suppression ratio | 70dB/55dB | ||||||||||||||||||||||||||||||
| <AM Tuner Section> | |||||||||||||||||||||||||||||||
| Receiving frequency range | 520 kHz to 1650 kHz | ||||||||||||||||||||||||||||||
| Sensitivity (IHF / loop antenna) | 10 μ V / 200 μ V/m | ||||||||||||||||||||||||||||||
| Signal-to-noise ratio (30% modulation, 1 mv input) | 55dB | ||||||||||||||||||||||||||||||
| Harmonic distortion factor (1000 kHz) | 0.4% | ||||||||||||||||||||||||||||||
| Selectivity (IHF) | Wide:30dB Narrow:50dB |
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| Frequency Response (Wide) | 30 Hz to 6 kHz | ||||||||||||||||||||||||||||||
| <Output Level / Impedance> | |||||||||||||||||||||||||||||||
| FM (1 kHz, 100% Dev.) | Fixed : 0.75V/1.8k Ω | ||||||||||||||||||||||||||||||
| AM (400 Hz, 30% Mod.) | Fixed : 0.25V/1.8k Ω | ||||||||||||||||||||||||||||||
| <General> | |||||||||||||||||||||||||||||||
| Rated power consumption | 14W (Electrical Appliance and Material Control Law) | ||||||||||||||||||||||||||||||
| Pwer | 100 VAC, 50/60Hz | ||||||||||||||||||||||||||||||
| External dimensions | Width 440x Height 78x Depth 337 mm | ||||||||||||||||||||||||||||||
| Weight | 4.7kg | ||||||||||||||||||||||||||||||