KENWOOD D-3300T
¥ 140,000 (released in 1986)
Commentary
An FM tuner developed with the aim of accurately conveying the large amount of information in digital source broadcasting without being aware of the transmission space.
Because the tuner handles complex waveforms that are completely different for each block, the conventional layout has been adversely affected by a mixture of signals for both the positive power supply and GND.
In order to solve this problem, we have developed and adopted a new pentacle circuit after solving the problems of tuners such as circuit design, ground point concept, and stability of high-frequency amplifier.
In this pentacle circuit, each stage is arranged around the power supply, and the power supply and stage are connected by the shortest path. The positive side power supply and GND are connected to each stage in the shortest way. At the same time, the GND of the signal system is treated separately from the power supply GND for each stage, and grounded at one point on the front end.
As a result, there is no mutual interference between the stages, no unnecessary signal is added to the positive power supply or GND, and the low-level reproduction capability is greatly improved.
We use high-grade parts such as a power transformer, Chemicon, and a copper heat sink for the power supply section, and a copper shield cover for the front end.
A direct-linear reception synthesizer is installed to suppress intermodulation and to obtain the best IM characteristics.
By improving front-end IM characteristics, suppressing intermodulation, and greatly reducing noise level, excellent SN can be obtained in all reception band from 70 mhz to 90 mhz.
In order to reduce stereo distortion, a distortion collecting circuit is installed.
In this circuit, a steep filter close to an ideal filter is used to eliminate adjacent station interference, which has a large influence, and the two signal selectivity is improved to 70 dB. In addition, the distortion factor of the IF filter is canceled in cooperation with DLLD.
In other words, only the harmonic distortion component generated by the IF filter is extracted and canceling up to the fourth order distortion, stereo distortion is reduced.
The audio signal system, including the MPX section, is designed for low distortion, low noise, and wide dynamic range.
The Direct Pure Decoder in the MPX section uses an analog multiplier based on a new principle. In addition, many low-noise, high-slew rate operational amplifiers are used in the amplifier system to improve the quality of FM signals.
A newly developed direct linear loop detector is installed in the detection system.
By directly linearizing the 10.7 MHz IF signal and configuring it with a closed-loop detector, and by installing a distortion correction circuit in the closed-loop, we aim to 0 the nonlinear distortion of the VCO and the distortion generated by the IF filter.
In addition, since DLLD is a closed-loop detector, noise generated in the loop is suppressed and it becomes a detector with high SN.
The stereo demodulation circuit employs a direct pure decoder (DPD) that multiplies the detection output by a pure sine wave with no components other than 38 kHz. There is no low-pass filter such as a clean reception filter in the signal line, so there is no phase rotation and high separation is obtained.
In the front-end section, we have introduced our own FM technology to eliminate interference from TV radio waves.
In addition, it is equipped with an RF selector to enable high-quality reception even when there is a close high-output station. It is direct for strong electric fields and can change the distance for weak electric fields.
It is equipped with various functions such as multi-dimensional tuning, Rec calibration & modulation level meter, 16-station preset function, 3-station program function, antenna A/B switching for FM multi-station, IF / Wide/Narrow switching, auto-tuning, auto Chinese arrowhead and manual Chinese arrowhead function.
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Model Rating
| Type | FM stereo tuner | ||||||||||
| Receiving frequency range | 76 MHz to 90 MHz | ||||||||||
| Antenna impedance | 75 Ω unbalance | ||||||||||
| Sensitivity (75 Ω) | Distance : 0.95 μ V/10.8 dBf Direct : 10 μ V/31.2 dBf |
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| SN ratio 50 dB sensitivity |
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| Harmonic distortion factor (100% modulation) |
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| SN ratio (100% modulation, 85 dBf input) | mono:100dB stereo:92dB |
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| Capture ratio | Wide:0.8dB Narrow:2.0dB |
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| Effective selectivity (IHF) | Wide:70dB Narrow:100dB |
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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 Interference Ratio (84 MHz) | 110dB | ||||||||||
| Spurious interference ratio (84 MHz) | 100dB | ||||||||||
| AM suppression ratio (65.2 dBf) | 70dB | ||||||||||
| Subcarrier suppression ratio | 75dB | ||||||||||
| Output Level / Impedance |
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| Power supply voltage | 100 VAC, 50Hz/60Hz | ||||||||||
| Rated power consumption (Electrical Appliance and Material Control Law) | 20W | ||||||||||
| External dimensions | Width 475x Height 88.5x Depth 327 mm | ||||||||||
| Weight | 6.0kg | ||||||||||
| Attachment | T-type antenna Antenna adapter Double pin cord |