Optonica ST-3535 tuner

Outstanding Features

Multipath Detector Circuit

The ST-3535 incorporates a meter and terminals for an oscilloscope to detect multipath distortion and a built-in circuit to monitor its composition. The degree of multipath distortion is indicated by the meter, by the sound volume or by the waveform on the oscilloscope. Therefore, the antenna direction is easily and accurately reset. The circuit also improves FM listening and assures optimum recording.

Built-in Air Check Calibrator

This is a unique device for accurate "FM Air Check". Just flip on the switch and a level signal equivalent to that of the FM signal is generated. Then all you have to do is set the recording level to 0 VU on the deck.

Monolithic ICs are employed, Inter-station noise is eliminated by the muting switch

A hi-blend switch to reduce noise during reception of weak FM stereo signal

Variable audio output level control

Signal strength meter - this meter responses in proportion to the degree of signal intensity, thereby rendering effortless tuning under any condition

Easy-to-read-and-tune FM linear dial with a frequency-linear type variable capacitor, 8-11/16" wide scale, large flywheel and smooth tuning mechanism

FM signal input attenuator reduces distortion due to high signal input levels for stable FM reception

The FM antenna is equipped with dual terminals for 300 ohms or 75 ohms

Composite signal output terminal is provided for future possible FM 4-channel broadcasting

 

Outstanding Performance

Dual-gate MOS FETs and FM front end equipped with 4-gang linear tuning capacitor

The FM front end consists of a 4-gang capacitor that employs a double-tuned RF amplifier stage and a mixing stage. Remarkable performance characteristics such as 2,5 µV IHF sensitivity. 80 dB spurious response rejection ratio and 85 dB IF rejection ratio are attained. These figures assure high sensitivity and stable reception.

IF stage designed for high selectivity and interference protection

To obtain both ultra-low distortion characteristics and high selectivity, a phase linear ceramic filter and differential IC circuit are employed to make the phase characteristics at the IF stage linear. The band pass characteristics is also greatly improved.

PLL MPX circuitry

The PLL (phase-Locked Loop) circuit replaces the conventional coils and associated components with ultra-reliable integrated circuitry. The PLL circuit automatically compensates for phase-shift, thus ensuring stable separation for long periods of use.

A sub-carrier trap with inductive M-type filter is employed

 

Specifications

FM Section

Frequency Range: 87,6 - 108 MHz

Antenna Input:  75 Ω  (unbalanced); 300 Ω  (balanced)

Sensitivity (IHF)

Mono :  2,5 µV (300 Ω  antenna terminal)

Image Rejection:  80 dB

IF Rejection:  85 dB

Spurious Response Rejection:  80 dB

AM Suppression:  43 dB (mod. 30% AM by 1 kHz and 100% FM by 400 Hz)

Capture ratio:  1,5 dB

Selectivity:  65 dB (±400 kHz, 65 kHz Dev.)

Signal-to-Noise Ratio

Mono :  65 dB (75 kHz  Dev. 1 kHz)

Total Harmonic Distortion

Mono :  0,4% (75 kHz  Dev. 1 kHz)

Stereo :  0,8% (75 kHz  Dev. 1 kHz)

Stereo Separation

34 dB :  1 kHz, 75 kHz Dev.

25 dB :  50 Hz - 10 kHz

Frequency Response:  45 Hz - 13 kHz (±1,5 dB)

AM Section

Frequency Range:  520 - 1620 kHz

Antenna:  Built-in ferrite loopstick antenna AM external antenna terminal

Sensitivity:  400 µV /m (IHF, ferrite antenna)

Selectivity:  25 dB (at 1,000 kHz)

Signal-to-Noise Ratio:  35 dB

Image Rejection:  55 dB (at 600 kHz)

Total Harmonic Distortion :  1,5%

Audio Section

FM Output

Fixed :  0,5 V (1 kHz, 75 kHz Dev.)

Variable :  0 - 1,0 V (1 kHz, 75 kHz Dev.)

A Output

Fixed :  0,15 V (30% Mod.)

Variable :  0 -0 ,3 V (30% Mod.)

Composit Signal Out Terminal:  Yes

General

Semiconductors:  2 MOS FETs; 5 ICs plus 1 aux IC; 10 Transistors plus 16 aux Transistors; 6 Diodes plus 15 aux Diodes

Power Requirements:  AC 120 50/60 Hz

Power Consumption:  24 W

Dimensions (W x H x D):  17-3/8" x 5-5/8" x 15"

Weight:  2 lbs