meduci AM STEREO Owner'S Manual Download Page 1

Safety and Operating Use Instructions / Owner Manual

FEATURES

Updated 03/24/20

meduci Advanced Wide Voltage I.F and C-QuAM High Quality AM Stereo Decoder Converter.

Signal Quality Detector that analyzes signal strength, signal-to-noise ratio, and stereo pilot 

tone prior to switching to the stereo mode.

Precision AM Stereo Pilot Tone Detector.

I.F Amplifier with I.F AGC Circuit.

VCO Shutdown Mode at weak I.F signal input.

Typical I.F Input Impedance: 2 k-ohms 

Class-A biased discrete transistor audio output buffered amplifier stages -- Audio purity 

without crossover distortion. 

Decodes Motorola C-QuAM analog AM Stereo broadcasts, where available, with automatic 

stereo detection. 

WARNING:  All host tuner and receivers  must NOT be energized or connected to power source when installing this AM 
stereo decoder product.  There are lethal dangerous voltages present within all consumer electronics devices.  You can be 
killed when in contact with these high voltages.  Refer AM stereo decoder installation and modification to be performed 
by qualified experienced service personnel only. 

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Summary of Contents for AM STEREO

Page 1: ...t Impedance 2 k ohms Class A biased discrete transistor audio output buffered amplifier stages Audio purity without crossover distortion Decodes Motorola C QuAM analog AM Stereo broadcasts where available with automatic stereo detection WARNING All host tuner and receivers must NOT be energized or connected to power source when installing this AM stereo decoder product There are lethal dangerous v...

Page 2: ...LEFT RIGHT AUDIO STEREO LED blue I F INPUT yellow GROUND black meduci AM STEREO DECODER CONVERTER PC BOARD MODULE 2 Mounting Hole 12 V D C red FORCED MONO green ...

Page 3: ...ood strong and solid AM stereo signal an un degraded mono output will be provided from both audio channels This add on decoder functions with the Motorola C QuAM stereo system and provides full separation stereo reception from local AM stations transmitting the C QuAM encoded format where available It is best to install this decoder into digitally tuned PLL quartz synthesized host AM tuner or rece...

Page 4: ...uld be achieved 1 Vacuum tube radios are unacceptable You will undoubtedly experience issues due to the high voltages and extreme operating temperatures involved 2 Cheap pocket radios clock radios small table radios portable radios and the like should not be used They typically have narrow I F bandwidths poor station sensitivity and self generated phase and frequency modulations that can seriously...

Page 5: ...tuned Radios ETR with PLL quartz crystal synthesized front ends are best adapted to AM stereo reception due to their precise automatic tuning and better immunity to tuning disturbances However those types of receivers are not guaranteed to be trouble free Phase modulation can originate from the PLL comparison frequency and may appear as an audible tone in the recovered audio from the AM stereo dec...

Page 6: ...receiver or tuner AGC voltages are generally obtained from the detector so the existing detector circuit should be retained To avoid conflict with the two audio channels coming from the stereo decoder the tuner s existing mono audio outputs first must be disconnected usually at or near the band switch Decoder board may be mounted in any convenient place inside your host tuner however keep it away ...

Page 7: ...o 120 mV p p as double sideband AM C QuAM signal as measured with your oscilloscope probe During final installation ensure that all connections are securely connected and correctly connected to host tuner Once the installation has been completed it is necessary to carry out the set up procedure You are now ready to check for AM stereo reception Tune local AM station that is known and confirmed to ...

Page 8: ...lytic Aluminum Capacitors 2 47uFd Capacitors 1 MC13028AD AM Stereo IC Chip 1 CFU450B Ceramic Filter 1 Custom Printed Circuit Board Double Sided 8 Your user provided stereo LED s short lead cathode should be soldered to the ST IND connection on your AM_ST decoder board Your stereo LED s long lead anode should be soldered directly to the 8 volt hole on your AM_ST decoder board this is in the upper l...

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