TX-9100 FEATURES The FM Front End From the incoming antenna signal, the desired portion is selected before the first amplification stage - by a 5- ganged variable capacitor (The tuning dial is of course marked in linear intervals.). 2-stage RF amplification as well as the mixer are equipped with dual gate metal oxide semiconductor field effect transistors (MOS FUT) of special low- noise characteristics, whereby tuner sensitivity, image rejection and spurious rejection are raised to the theoretical limits, and crossmodulation is eliminated. Between the local oscillator and the mixer circuit, a special buffer amplifier is provided to assure stable operation in very strong as well as extremely weak singal areas. The IF Stages All six limiter stages in the intermediate frequency (IF) stretch arc equipped with ICs of highly stable operating characteristics. This design accounts for the tuner's outstanding performance in regard to capture ratio (ability to distinguish between wanted and unwanted signals on the same frequency band), signal-to-noise ratio (meaning freedom from noise and hiss) and AM rejection (i.e. suppression of noise signals from motors, etc.). Filters are not of the conventional IC type, but are specially developed “phase linear" ceramic components which provide sharp, stable cutoff characteristics without causing any phase distortions. Adjacent-channel selectivity of this tuner is so sharp that even the best laboratory instruments can hardly measure it. The FM MPX Decoder The design principle of the “phase lock loop" is applied in this circuit it has no inductances or capacitances which could cause phase shifts and distortions. Any phase dislocation that might occur is automatically detected and compensated by a loop circuit. This results in an unprecedented high degree of stability irrespective of temperature or humidity changes. FM stereo channel separation always remains sharp and clear-cut, throughout the audiofrequency range (in convent ional tuners, separation often deteriorates at the higher frequencies). Also, great care has been taken to eliminate SCA interferences, beat, and leakage of the 38kHz switching carrier. Pulse Noise Suppressor Irritating pulse noise, mostly caused by automobile ignitions, cannot be completely eliminated in the limiter stages if the signal received is weak. Therefore model TX-9100 is equipped with a special pulse noise suppressor circuit which detects the presence of (frequency- and/or amplitude modulated) pulse noise and eliminates it from the audio signal, without however affecting the wanted signal in any way. MPX Noise Filter High-frequency noise sometimes present in weak FM stereo reception can be somewhat reduced by the MPX noise filter. Auxiliary Controls and Facilities These include a signal strength tuning meter {lor FM and AM), a center-zero tuning meter (for FM), separate output level controls for AM and FM, and a built-in headphone amplifier, headphone jack and headphone volume control. On the rear panel, you find a swivel-type ferrite bar antenna for AM reception, variable and fixed output jacks, FM antenna connectors for 300Ω feeder wire and 75S2 coaxial cable, and a pair of FM multipath detector outputs which, when connected to an oscilloscope or the Pioneer Stereo Display unit SD-1 100, permit visual detection of multipath conditions. The AM Section Please note that the AM tuning dial, too, is marked in linear intervals for easy tuning. A large scale integrated circuit is used in the AM section, giving stable reception under all conditions. To apply a generous amount of feedback for the automatic gain control, a special “remote cutoff” transistor is used. AM output level remains constant regardless of incoming signal strength. For sharp selectivity, ceramic filters are used in the AM IF section. The TX-9100 is one of the very few tuners that deliver hi-fi-acceptable sound quality on AM, too. Positively Functioning Muting Circuit, Two Threshold Levels The FM muting circuit is an advanced design employing one MOS IC and one large scale IC. Muting of interstation noise is quick and responsive, even if you twirl the tuning knob rapidly. When the tuner picks up a station, however, the signal will not appear abruptly but will “fade in” quite naturally. This effect is achieved by using a semiconductor switch in combination with a relay. With the switch on the front panel, the muting threshold level the minimum signal strength that the muting circuit wili let pass — can be adjusted in two stages. Outward Appearance Matches Technical Excellence The easy-to-read and at the same time elegant, tuning dial and front panel, the natural-grain walnut cabinet - the Pioneer TX-9100 looks as good as it sounds. Its styling matches that of other Pioneer hi-fi components so that you can assemble a stereo system of unified elegance.