Carrier signals modulated by information (video and/or data) signals are
received through a cable and are converted to modulated signals at an
intermediate frequency. The IF signals are sampled at a particular
frequency to produce digital information signals. The digital information
signals are introduced to a variable interpolator which produces first
digital signals. The first digital signals are introduced to a complex
multiplier which produces second digital signals. The second digital
signals pass to an adaptive equalizer which selects for each of the
second signals in accordance with the amplitude of such second signals,
an individual one of a multitude of amplitude levels involved in
quadrature amplitude modulation. These selected amplitude levels
represent the information (video and/or data). The output signals from
the adaptive equalizer are introduced to a first signal recovery loop
which includes a first numerically controlled oscillator. The oscillator
operates upon the variable interpolator to obtain the production by the
variable interpolator of the first digital signals in the correct
subinterval of the time period that each of the digital information
signals is produced. The output signals from the adaptive equalizer are
also introduced to a second signal recovery loop which includes a second
numerically controlled oscillator. This oscillator operates upon the
complex multiplier to maintain the frequency of the second digital
signals at the frequency of the digital information signals.