Pioneer F-500
¥ 49,800 (released in 1979)
Commentary
An FM/AM tuner that employs a beatless pulse count method.
The detection circuit employs a pulse count method that pulses the FM signal and processes it digitally. This method is linear detection and does not degrade the distortion factor characteristics especially at low and high frequencies.
In addition, to take full advantage of the advantages of this pulse counting method and obtain a higher SN ratio, we have adopted a double conversion method in which the IF frequency of 10.7 MHz is reduced to the second IF frequency of 1.26 MHz and then detected. In order to solve the problem with this double conversion method double conversion method, we have adopted a linear multiplier for the second mixer stage and a push-pull oscillator for the second local stage.
In addition, a DC servo circuit is used from the detection output to the MPX output for a direct connection system without a coupling capacitor to reduce the effect of the capacitor on sound quality.
The front-end section has a single-double-single configuration consisting of a 5-series varicon, DD MOS and D MOS FETs, and an air-core coil is used for the RF coil to achieve both high practical sensitivity and high interference rejection capability.
Two stage switching of Wide and Narrow is adopted for the IF part.
When narrow is used, a total of five ceramic filters with two elements are used to obtain high selectivity. When Wide is used, a ceramic filter with flat group delay characteristics and low distortion factor enables reception with low distortion factor.
The MPX section uses a direct-through switching method in which the signal itself does not pass through the active element, and the necessary signal flows as it is to the output, and the unnecessary signal flows to the ground.
In addition, a pilot signal auto-cancel circuit is installed to increase the bandwidth.
It is equipped with a touch sensor servo lock circuit. Turn the tuning knob and release the knob at the tuning point to lock the frequency.
The IF section of the AM tuner is also equipped with Wide/Narrow switching. Wide provides broadband characteristics with the highest priority on sound quality, while narrow provides high selectivity.
Equipped with MPX noise filter, bus muting circuit, Rec level check mechanism and multi-pass terminals.
.JPG)
Model Rating
| Type | FM/AM Tuner | |||||||||
| FM Tuner Section | ||||||||||
| S/N ratio 50 dB sensitivity | Mono : 1.8 μ V/16.2 dBf (new IHF) Stereo : 20.0 μ V / 37.2 dBf (new IHF) |
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| Practical sensitivity | Mono : 0.95 μ V/10.8 dBf (new IHF) | |||||||||
| SN ratio (at 85 dBf input) | mono:90dB stereo:85dB |
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| Harmonic distortion factor |
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| Capture ratio | wide:0.8dB narrow:2.0dB |
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| Effective selectivity | wide:40dB(400kHz) narrow:60dB(300kHz) |
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| Stereo separation | wide:60dB(1kHz) 50 dB (20 Hz to 10 kHz) |
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| Frequency characteristic | 20 Hz to 15 kHz ± 0.5 dB | |||||||||
| RF intermodulation characteristic | 97 db (2.5 mhz detuning) 85 db (800 khz detuning) |
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| Image interference ratio | 120dB | |||||||||
| IF interference ratio | 100dB | |||||||||
| Spurious interference ratio | 110dB | |||||||||
| AM suppression ratio | 70dB | |||||||||
| Subcarrier suppression ratio | 70dB | |||||||||
| Muting action level | 4.9 μ V (25.0 dBf) | |||||||||
| Antenna input impedance | 300 Ω Balanced Type, 75 Ω Unbalanced Type | |||||||||
| <AM Tuner Section> | ||||||||||
| Practical sensitivity | 300 μ V/m (bar antenna) 15 μ V (external antenna) |
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| Selectivity | Wide:18dB Narrow:50dB |
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| Signal-to-noise ratio | 50dB | |||||||||
| Image interference ratio | 45dB | |||||||||
| IF interference ratio | 40dB | |||||||||
| <General> | ||||||||||
| Output Level / Impedance | FM (100% modulation) Fixed : 650mV/2.2k Ω Variable : 0 mv ~ 1.3V/2.2k Ω AM (30% modulation) Fixed : 200mV/2.2k Ω Variable : 400mV/2.2k Ω |
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| Multipath output | Vertical : 130mV/10k Ω Horizontal : 400mV/10k Ω |
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| Power supply voltage | 100 VAC, 50Hz/60Hz | |||||||||
| Power consumption | 22W | |||||||||
| External dimensions | Width 420x Height 98x Depth 403 mm | |||||||||
| Weight | 6.8kg | |||||||||