ROTEL RT-2100
¥ 98,000 (around the late 1970 s?)
Commentary
FM stereo tuner using quartz lock system.
Quartz lock system with crystal oscillator is adopted.
The quartz-locked system constantly compares the accurate 10.7 MHz produced by the crystal oscillator with the intermediate-frequency amplified (IF) 10.7 MHz. When a difference occurs, the phase comparator produces a plus / minus difference signal, and a low-pass filter controls the local oscillator. Quartz is insensitive to changes in humidity or temperature, so the oscillation frequency remains locked, eliminating post-tuning drift.
In addition, a touch lock-off system is adopted, and the lock is released while the tuning knob is touched, and the quartz lock works the moment the hand is released.
Uses a tuning method with an LED indicator.
When the tuning knob is touched, the induced voltage is detected and the quartz lock is released. At this time, the local frequency changes linearly. When the dial indicator comes close to the desired radio wave (± 100 kHz), the side indicator lights. When the indicator comes close to the desired radio wave, the green LED in the center lights. This indicates full synchronization. When the indicator comes close to the desired radio wave, the LED in the quartz lock indicator glows green, indicating that the lock has been achieved. When the knob is released, the LED in the quartz lock indicator lights green.
The front end section uses a frequency linear type precision 5-row varicon.
The RT the RT-2100 uses three dual-gate MOS FETs for high sensitivity and excellent interference rejection.
The bandwidth of the IF section can be switched in two stages, and conditions can be set according to reception conditions.
By selecting NARROW when radio wave conditions are poor, high selectivity characteristics can be obtained.
The MPX section is equipped with a carrier canceler circuit that cuts the pilot signal (19 kHz). The LC block filter and PLL IC, which take care of the attenuation of the sub-carrier signal (38 kHz), ensure a wide range by suppressing the high-frequency degradation.
Equipped with tape deck and level check function.
When the REC CHECK switch is turned on, a dial tone of 400 Hz will be output. During an air check, the deck level will be set to reference (0 dB).
Equipped with multipath detection function.
For RT-2100, the signal indicator shows the degree of multipath.
It is equipped with a high-blend switch that demonstrates power in weak electric field reception.
Model Rating
| Type | FM stereo tuner | ||||
| Sensitivity (IHF) | Mono : 9.3dBf/1.6 μ V (S/N 26 dB) Stereo : 36dBf/35 μ V (S/N 50 dB) |
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| Signal-to-noise ratio (IHF) | mono:80dB stereo:75dB |
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| Harmonic distortion factor |
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| Capture ratio | 1dB | ||||
| Effective selectivity (IHF) | narrow:80dB | ||||
| Frequency characteristic | 30 Hz to 15 kHz ± 0.2 dB | ||||
| Stereo separation | 47dB(1kHz) | ||||
| Image interference ratio | 115dB | ||||
| IF interference ratio | 115dB | ||||
| AM suppression ratio | 65dB | ||||
| Muting | 5 μ V | ||||
| External dimensions | Width 482x Height 143x Depth 328 mm | ||||
| Weight | 7.5kg |