ONKYO Integra T-419

Commentary

This is an FM stereo tuner developed by Integra's FM engineering team by drawing on its know-how.

In the front end section, in addition to a high-precision 7-row varicon with triple tuning input stage, a high-linearity dual-gate MOS FET is adopted for an RF amplifier and a balanced mixer.
Furthermore, in consideration of the difference in radio wave conditions in the receiving area, we have developed an IF section with two stage bandwidth switching between WIDE (high sensitivity) and NARROW (high interference rejection performance) without changing the input triple configuration, thereby achieving clear reception performance.

The IF section uses a D-MOS FET for the input stage that takes advantage of the reception performance of the front end. It also consists of a linear phase filter with flat delay characteristics and eight interstage high-slew rate double-base differential ICx units.
The bandwidth is automatically switched by the S/N detection circuit between WIDE (4-element filter) and NARROW (+ 8-element filter), enabling reception with optimum audio characteristics depending on the radio wave condition.

We have developed and adopted a Cerasoid detector for the detector that demodulates FM carrier waves into audio signals.
The principle is that the mixer lowers the 10.7 MHzFM wave of the IF output to 1.68 MHz and then the limiter shapes it into a square wave. The high-precision square wave directly controls the sawtooth wave to detect the relative density of the sawtooth wave and extract an audio demodulation signal with a voltage completely inversely proportional to the frequency.

We have developed a quartz PLL circuit that uses a crystal oscillator to obtain a stable comparison frequency within 19 kHz ± 2 Hz. This circuit reduces the characteristic degradation caused by the phase difference with the 19 kHz pilot signal to the limit, and has succeeded in extracting a pure 38 kHz switching signal from the pilot signal included in the composite signal.
In addition, a high-speed D-MOS FET with a rise of + 1n/sec is adopted as a switching element that separates the composite signal into LR, and the distortion at the rise and fall part due to the slow switching speed is cleared.
In addition, to prevent mixing of pilot signals into audio signals, the MPX input stage is equipped with a pilot auto-canceler with a sine wave function to cope with severe fluctuations in the signal level of the station.

All audio circuits after the detector are composed of a servo operational DC amplifier, and a low noise operational amplifier IC is used for the servo amplifier that controls the DC amplifier.

Quartz lock system for perfect tuning.

The frequency display is a quartz digital readout.

Touch sensor tuning.

Equipped with DC active low-pass filter.

Bus-earth line is adopted. IF / MPX independent power supply part is adopted.

Equipped with input level detection type automatic noise reduction.

2-stage switching FM muting

Equipped with F-type connector antenna terminal for switching between A and B2 systems.

Equipped with a signal meter of linear type up to 100 dBf and a deviation meter with multi-path meter switching.

Equipped with 400 Hz, 50% modulation air check calibrator.

Equipped with level variable output terminal and fixed output terminal for recording.

Model Rating

Type	Super Servo Triple Quartz FM Stereo Tuner
FM Tuner Section
Receiving frequency	76 MHz to 90 MHz
Practical Sensitivity (75 Ω / IHF)	RF Wide : 0.95 μ V/10.8 dBf RF Narrow : 1.75 μ V/16.1 dBf
S/N50dB sensitivity (75 Ω / IHF)	RF Wide : 1.7 μ V/15.8 dBf
Intermodulation interference ratio (± 1 mhz / ± 2.5 mhz)	RF Wide:90dB/105dB RF Narrow:110dB/115dB
Image Interference Ratio (83 mhz)	RF Wide:120dB RF Narrow:120dB
IF Interference Ratio (83 MHz)	RF Wide:125dB RF Narrow:125dB
Signal-to-noise ratio	mono:90dB stereo:86dB
Spurious interference ratio	RF Wide:125dB RF Narrow:125dB
Two signal selectivity (± 400 kHz detuning)	IF Wide:60dB IF Narrow:90dB
AM suppression ratio	IF Wide:65dB IF Narrow:55dB
Capture ratio	IF Wide:1.0dB IF Narrow:1.5dB
Distortion factor	Mono, 400 Hz : 0.02%(IF Wide) 0.05%(IF Narrow) Mono, 50 Hz to 10 kHz : 0.05%(IF Wide) 0.15%(IF Narrow) Stereo, 400 Hz : 0.04%(IF Wide) 0.15%(IF Narrow) Stereo, 50 Hz to 10 kHz : 0.1%(IF Wide) 0.4%(IF Narrow)
Frequency characteristic	20 Hz ~ 15000 Hz + 0.2 -0.8 dB
Antenna impedance	75 Ω
Stereo separation	1kHz: 58dB(IF Wide) 48dB(IF Narrow) 100 Hz to 10 kHz : 50dB(IF Wide) 40dB(IF Narrow)
Carrier leak	-70dB
Output Voltage / Impedance	Variable Output : 0 ~ 1200 mV / 80 Ω at Maximum 450mV/6k Ω
<General>
Semiconductor used	53 ic, 116 tr (7 fet), 71 di
Pwer	100 VAC, 50/60Hz
Power consumption	36W (Electrical Appliance and Material Control Law Standard)
External dimensions	Width 435x Height 108x Depth 384 mm
Weight	9kg