Left and right audio outputs have nominal one-
volt “line” level and are
directly connected to the tuner’s internal audio band
-switch. Remember to
first disconnect the mono audio output from the host receiver. Stereo
indicator output is ready for connection to user-supplied LED indicator.
Alternately, the wire can be connected to the FM stereo decoder’s indicator
pin, if applicable. Please consult meduci for technical guidance, if needed.
Ensure that at least +10 volts D.C is applied to power input of decoder
board (observe correct power polarity). Red wire is for the positive voltage
from tuner’s power supply, and the black wire is for the tuner’s negative
ground connection. Measure the I.F input signal (it should be in the range from
90- to 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 be broadcasting the C-QuAM format. Ensure
that the stereo LED glows after a few seconds of receiving desired AM stereo
station. Note that accurate tuning and a very strong signal is necessary to
obtain good stereo reception.
Proven conversions
Carver TX-2 was successfully modified. Decoder was mounted inside tuner
using stand-
offs. Existing power source was verified to be switched “on” only
when AM band was selected. I.F was tapped from tuner chip. Mono AM audio
was disconnected inside tuner. Left/Right wires were spliced over FM audio.
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