Reduced cost saw-less catv rf tuner circuit for use in a cable modem

An image reject filter for use in a cable modem, comprising:

• a band pass filter coupled to an intermediate frequency (IF) signal input and having a first filter response;
• a buffer coupled to the output of said band pass filter;
• a low pass filter coupled to the output of said buffer and having a second filter response, said low pass filter operative to generate a filtered output signal therefrom;
• and
• wherein said first filter response combined with said second filter response yields a combined response operative to remove aliasing in said IF input signal produced during one or more previous mixing stages.

A receive signal path for use in a Data Over Cable Service Interface Specification (DOCSIS) compatible cable modem, comprising:

• a tuner integrated circuit (IC) operative to generate an intermediate frequency (IF) signal output in accordance with an RF input signal and a channel reference signal;
• an image reject filter coupled to said IF signal output and operative to remove aliasing therefrom and to generate a filtered IF signal thereby;
• and
• a PHY circuit comprising a digital channel selection filter coupled to said filtered IF signal and operative to output one of a plurality of channels in accordance with a corresponding tune command.

A cable modem, comprising:

• a memory;
• one or more interface ports;
• a single chip tuner integrated circuit (IC), said tuner IC comprising:
• a frequency reference input;
• means for generating a channel reference signal from said frequency reference input in accordance with a tune command signal;
• a CATV radio frequency (RF) receive signal input;
• a tuner circuit operative to mix said RF receive signal with said channel reference signal to yield an intermediate frequency (IF) signal thereby;
• an off-chip image reject filter coupled to said IF signal and operative to remove aliasing therefrom and to generate a filtered IF signal thereby;
• a PHY circuit coupled to said tuner, said PHY circuit comprising a digital channel selection filter coupled to said filtered IF signal and operative to output one of a plurality of raw video channel streams in accordance with a corresponding tune command;
• and
• a processor coupled to said memory, said one or more interface ports, said tuner and said PHY circuit, said processor operative to implement a media access control (MAC) layer operative to generate one or more output video streams from said plurality of raw video streams input thereto.