Pioneer F-700
¥ 65,000 (released in 1979)
Commentary
An FM stereo 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 is a push-pull configuration composed of 7 series varicon and DD MOS FET (double diffused FET).
As a result, a large dynamic range can be obtained, which leads to a decrease in practical sensitivity. Moreover, various interference rejection capabilities such as RF intermodulation characteristics are greatly improved.
In addition, a balanced mixer using a DD MOS FET improves the RF intermodulation characteristics.
The IF section adopts two stage switching between Wide and Narrow.
The Wide IF circuit consists of a low-distortion SAW filter and a ceramic filter with flat group delay characteristics and low distortion factor. The Narrow IF circuit has three additional narrow-band ceramic filters and two additional limiter ICs to improve selectivity.
The MPX section uses a direct-through MPX, so that the signal itself does not pass through the active element, the necessary signal is output as it is, and the unnecessary signal is grounded.
As a result, the distortion factor and S / N ratio are improved because there are no effects such as transistor noise components, nonlinearity and input level limitation.
In consideration of sound quality, a coreless low-pass filter that does not use magnetic materials is adopted.
As a result, the third order distortion caused by the magnetic material is reduced to approximately 1/10 to 1/30 compared to the conventional one.
It is equipped with a touch sensor servo lock. When you turn the tuning knob and release the knob when the pointer reaches the desired broadcasting station, the frequency is locked at this tuning point.
The dial indicator consists of three LEDs running : a green LED lights up near the broadcasting station, the center LED lights up red at the proper tuning point, and the LED turns green when the tuning knob is released to indicate that the frequency is locked.
Equipped with a meter that switches the deviation / Multipash with a switch.
Equipped with Rec level check and auto blend function.
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Model Rating
| Type | FM stereo tuner | |||||||||
| 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:92dB stereo:87dB |
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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:50dB(400kHz) narrow:65dB(300kHz) |
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| Frequency characteristic | 20 Hz to 15 kHz ± 0.5 dB | |||||||||
| RF intermodulation characteristic | 106 db (2.5 mhz detuning) 91 db (800 khz detuning) |
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| Image interference ratio | 120dB | |||||||||
| IF interference ratio | 120dB | |||||||||
| Spurious interference ratio | 120dB | |||||||||
| AM suppression ratio | 70dB | |||||||||
| Subcarrier suppression ratio | 70dB | |||||||||
| Muting action level | 4.9 μ V (25 dBf) | |||||||||
| Antenna input impedance | 75 Ω Unbalanced Type | |||||||||
| Output level / impedance (100% modulation) | Fixed : 650mV/2.2k Ω Variable : 0 mv ~ 1.3V/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 | 25W | |||||||||
| External dimensions | Width 420x Height 98x Depth 393 mm | |||||||||
| Weight | 7.5kg |