Audio Database

TU-451
Commentary

FM/AM tuner equipped with drum type long scale dial.

The front end uses a frequency linear 3-row varicon, RF1-stage, and junction FET.

The IF amplifier employs a two stage switching method between the wide (wide band) and narrow (narrow band) of the IF amplifier to achieve both audio transmission characteristics and interference rejection capability.
The wide-band filter consists of a linear-phase two element ceramic filter and an LC filter, enabling reception with excellent sound quality and sound field feeling. The narrow-band filter improves the effective selectivity to enable better separation, and the inter-station noise muting capability is increased to 16 dB to improve the channel selection feeling.

The AM tuner uses an IC to increase sensitivity, and a ceramic filter to improve separation performance and distortion factor.

Model Rating
Type FM/AM Tuner
FM Tuner Section
Receiving frequency range 76 MHz to 90 MHz
Intermediate frequency 10.7MHz
Practical sensitivity (IHF) 1.9 μ V
S/N50dB sensitivity Mono : 3.5 μ V
Effective selectivity (IHF) wide:30dB
narrow:80dB
Image Interference Ratio (83 mhz) 60dB
IF Interference Ratio (83 MHz) 80dB
Spurious interference ratio (83 MHz) 75dB
AM suppression ratio (IHF) 60dB
Capture ratio wide:1.0dB
narrow:1.6dB
Frequency characteristic 30 Hz ~ 15 kHz + 0 -2dB
Carrier leak 40dB
Signal-to-noise ratio mono:75dB
stereo:70dB
Total harmonic distortion rate (1 kHz) Mono (at 100% modulation) : 0.07% (wide), 0.3% (narrow)
Stereo (90% modulation) : 0.09% (wide), 0.5% (narrow)
Stereo separation Wide : 50 dB (1 kHz), 45 dB (50 Hz to 10 kHz)
Narrow : 40 dB (1 kHz), 35 dB (50 Hz to 10 kHz)
<AM Tuner Section>
Receiving frequency range 525 kHz to 1,605 kHz
Intermediate frequency 455kHz
Practical Sensitivity (S/N 20 db) 300 μ V/m (using attached bar antenna)
20 μ V (External Antenna Terminal Used)
Selectivity (± 10 kHz) 33dB
Image Interference Ratio (1 MHz) 55dB
IF Interference Ratio (1 MHz) 40dB
Signal-to-noise ratio 55 dB (field strength 100mV/m at 30% modulation)
Total harmonic distortion factor 0.8% (at an electric field strength of 10mV/m and 30% modulation)
<Audio Output>
Output Voltage / Impedance 0.7Vrms/2.5k Ω (at 100% modulation)
Level check voltage 0.35 Vrms (440 Hz, equivalent to 50% modulation)
<General>
Antenna terminal FM : Screw Type (300 Ω, 75 Ω)
AM : Ferrite Bar Antenna with Threaded External Terminal
Pwer 100 VAC, 50Hz/60Hz
Power consumption 8.5W
External dimensions Width 430x Height 144.5x Depth 303 mm
Weight 6.2kg