KENWOOD KT-880F
¥ 45,000 (released in 1985)
Commentary
4D system synthesizer FM/AM tuner equipped with 4 unique technologies.
Equipped with a direct linear reception circuit.
In the conventional synthesizer tuner, the phase of the local oscillation frequency and the reference signal are compared with the crystal accuracy to obtain a constant frequency. However, because of the error caused by the temperature change of the crystal clock, the high SN is obtained at 90 MHz, but the SN goes down at 76 MHz.
This is suppressed by the unique direct and linear reception circuit to enable clear reception.
A distortion correcting circuit is installed as an IF distortion correcting circuit.
In order to eliminate large adjacent station interference, a steep filter is adopted, and the harmonic distortion component generated by the filter is extracted and canceled by a unique distortion correction circuit.
It is equipped with a direct linear loop detector, a newly developed wide-band linear detector circuit.
By directly linearizing the 10.7 MHz IF signal and detecting it with a closed loop detector, and installing a distortion correction circuit in the closed loop, the non-linear distortion of the VCO and the distortion generated by the IF filter are reduced to 0.
Since the DLLD is a closed-loop detector, the noise generated in the loop is suppressed and the detector has a high SN ratio.
The newly developed DPD (direct pure decoder) MPX is used for stereo demodulation.
Unlike the conventional square-wave switching, the detection output is multiplied by a pure sine wave with no components other than 38 kHz. Therefore, a low-pass filter such as a clean reception filter is not required and interference is eliminated.
Dual gate -gate MOS FET is used in the RF amplifier and MPX section to significantly improve intermodulation characteristics.
It is equipped with a preset function for 16 random stations and a one touch channel selection function by auto-tuning.
You can record 3 stations by linking with the timer.
You can easily set the optimum recording level by installing a Rec calibration of -6dB at 100% modulation.
Model Rating
| Type | 4D System 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/10.8 dBf | ||||
| SN ratio 50 dB sensitivity | Mono : 1.8 μ V/16.2 dBf Stereo : 24 μ V/38.8 dBf |
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| Harmonic distortion factor (100% modulation) |
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| SN ratio (100% modulation, 85 dBf input) | mono:98dB stereo:88dB |
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| Capture ratio | 1.5dB | ||||
| Effective selectivity (IHF) | 60dB | ||||
| Stereo separation | 1kHz:68dB 50 Hz to 10 kHz : 43 dB 15kHz:38dB |
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| Frequency characteristic | 20 Hz to 15 kHz + 0.2 -0.8 dB | ||||
| Image interference ratio (84 MHz) | 90dB | ||||
| IF Interference Ratio (84 MHz) | 100dB | ||||
| Spurious interference ratio (84 MHz) | 100dB | ||||
| AM suppression ratio (65.2 dBf) | 65dB | ||||
| Subcarrier suppression ratio | 70dB | ||||
| Output Level / Impedance | FM (1 kHz, 100% modulation) : 0.6V/3.3k Ω | ||||
| <AM Tuner Section> | |||||
| Receiving frequency range | 531 kHz to 1602 kHz | ||||
| Sensitivity | 10 μ V / 300 μ V/m | ||||
| Harmonic distortion factor (1000 kHz) | 0.3% | ||||
| Image interference ratio (1000 kHz) | 40dB | ||||
| IF Disturbance Ratio (1000 kHz) | 50dB | ||||
| Selectivity (IHF) | 25dB | ||||
| Output Level / Impedance | 0.18V/3.3k Ω | ||||
| Signal-to-noise ratio (30% modulation, 1 mv input) | 50dB | ||||
| <General> | |||||
| Power supply voltage | 100 VAC, 50Hz/60Hz | ||||
| Rated power consumption (Electrical Appliance and Material Control Law) | 10W | ||||
| External dimensions | Width 440x Height 67x Depth 319 mm | ||||
| Weight | 3.3kg | ||||