‰  NOW 25 WPM  ‰  TEXT IS FROM OCTOBER 2018 QST  PAGE 45 ‰

SAMPLING ARCHITECTURE.  THAT IS, THERE ARE NO CONVERSION STEPS IN FRONT OF
THE ANALOG TO DIGITAL ADC CONVERSION IT ALL HAPPENS AT SIGNAL FREQUENCY.
THIS ARRANGEMENT HAS MULTIPLE ADVANTAGES.  THERE ARE NO NONLINEAR MIXER OR
CONVERTER STAGES BETWEEN INPUT AND OUTPUT, ELIMINATING IMAGES AND MANY
SOURCES OF BIRDIES, AS WELL AS PLACES FOR INTERMODULATION PRODUCTS TO HIDE.
THE DOWNSIDE IS THAT IF THE ADC IS OVERLOADED, OTHER PROBLEMS CAN ARISE.
THE IC 7610 TAKES PAINS TO REDUCE THE LIKELIHOOD OF THIS HAPPENING BY
SWITCHING IN FILTERS, INCLUDING A SWITCHABLE TRACKING FILTER DIGI SEL THAT
FOLLOWS THE TUNED FREQUENCY, AS WELL AS ATTENUATORS AND AMPLIFIERS IF
NEEDED AHEAD OF THE ADC FOR GAIN MANAGEMENT.  TO HELP AVOID RECEIVER
OVERDRIVE PROBLEMS, THE DISPLAY INCLUDES AN OVERLOAD INDICATOR OVF THAT
ILLUMINATES IF THE ADC OVERFLOWS DUE TO EXCESSIVELY STRONG SIGNALS.  THE
OPERATOR CAN ELIMINATE THE PROBLEM BY TURNING BACK THE PREAMP A NOTCH, OR
‰  END OF 25 WPM TEXT  ‰  QST DE W1AW  ƒ