TRIO KT-2200
¥ 99,800 (around 1983)
Commentary
This FM tuner was developed to improve the quality of FM broadcasting.
A non-spectrum IF system is adopted to achieve distortionless transmission.
This is a method that removes the FM spectrum when it enters the IF from the FM signal that always conveys information as a spectrum with a variable bandwidth. After the interference signal is removed through the IF filter, it is returned to the original FM signal for detection. This method suppresses distortion while maintaining the interference rejection capability.
The VCO (Voltage Controlled Oscillator) emits a 6.2 MHz signal with exactly the same shift as the received FM broadcast, and the subtraction mixer removes the FM shift of the signal so that "input signal - VCO oscillation signal = non-spectrum IF signal".
Therefore, the FM signal that passes through the IF bandpass filter becomes a 4.5 MHz signal with no FM spectrum, and by passing this non-spectral IF signal through the steep IF bandpass filter, high selectivity is ensured.
The second intermediate frequency signal of 4.5 MHz is passed through an adder mixer to add a 6.2 MHz signal again and returned to an intermediate frequency signal of 10.7 MHz with FM shift. The signal is guided by a demodulation signal from a limiter to achieve 0.005% transmission.
It uses a direct conversion system with excellent IM and large input characteristics.
When the RF selector is set to the Direct position, the input signal is directly input to the mixer without passing through the RF amplifier. Even when there is sufficient input or when there is a close high-power station, interference such as RF intermodulation and intermodulation is suppressed and sound with excellent SN ratio is extracted.
In addition, the distance position is designed with high sensitivity to catch Oire power stations and long-distance stations.
One point grounding has been realized by clarifying the reference point of each part and arranging the signal transfer of each part.
This eliminates the interference of signal current through the chassis, and the operation of each part from the receiver to the audio part is closely examined to reproduce high-quality FM sound.
Uses Sampling Hold MPX.
At the same time as improving the separation characteristics, since only the peak is sampled and held, there is little change in the amplitude of the 38 kHz component when modulation is applied, and dynamic carrier leakage due to changes in the modulation level of speech is reduced.
If a variable FM muting is adopted and the level is set to 5 stages, only a high output station with a good SN ratio can be caught. If the level is set to 1, even a weak distant station can be freely selected.
Model Rating
| Type | FM stereo tuner | ||||||||
| FM Tuner Section | |||||||||
| SN ratio 50 dB sensitivity (IHF / new IHF) | 1.7 μ V/15.9 dBf (Distance, mono) 20 μ V/37.3 dBf (Distance, stereo) 5 μ V/25.2 dBf (Direct, mono) 60 μ V/46.8 dBf (Direct, stereo) |
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| Sensitivity (IHF / new IHF) | 0.9 μ V/10.3 dBf (Distance) 4.0 μ V/23.3 dBf (Direct) |
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| Antenna impedance | 75 Ω unbalance | ||||||||
| Harmonic distortion factor |
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| Signal-to-noise ratio (85 dbf input) | mono:96dB stereo:86dB |
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| Capture ratio | 2.0dB(Narrow) 0.8dB(Wide) |
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| Effective selectivity | 55 dB (± 300 kHz, Narrow) 40dB(Wide) |
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| Stereo separation |
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| Frequency characteristic | 15 Hz to 15 kHz ± 0.5 dB | ||||||||
| Image interference ratio | 90dB(84MHz) | ||||||||
| IF interference ratio | 120dB(84MHz) | ||||||||
| Spurious interference ratio | 110dB(84MHz) | ||||||||
| AM suppression ratio | 75dB | ||||||||
| Subcarrier suppression ratio | 75dB | ||||||||
| Output Level / Impedance (1 kHz, 100% Dev) | 0.6V/2k Ω (Fixed) 1.2V/2k Ω (Variable) |
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| Multipath | 0.1V/10k Ω (Vertical) 0.7V/10k Ω (horizontal) |
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| <General> | |||||||||
| Rated power consumption | 11W (Electrical Appliance and Material Control Law) | ||||||||
| Pwer | 100 VAC, 50Hz/60Hz | ||||||||
| External dimensions | Width 440x Height 111x Depth 337 mm | ||||||||
| Weight | 5.4kg | ||||||||