Low-cost receiver using integrated inductors

A receiver comprising:

• a first amplifier having an input for receiving a radio frequency signal, and an output;
• a first filter having an input coupled to the output of the first amplifier, a tuning input, and an output, for substantially passing frequencies below a variable cutoff frequency, the variable cutoff frequency being less than an upper frequency threshold of the first filter;
• a second filter having an input coupled to the output of the first amplifier, a tuning input, and an output, for substantially passing frequencies within a band above a lower threshold frequency of the second filter and below an upper threshold frequency of the second filter;
• wherein the first filter comprises:
• a first variable capacitor having a first terminal coupled to the output of the first amplifier, a second terminal coupled to a power supply voltage terminal, and a control terminal for receiving a tuning signal;
• and
• an inductance leg having a first terminal coupled to the output of the first amplifier, and a second terminal coupled to the power supply voltage terminal, the inductance leg including a first inductor and having an effective resistance in series with the inductor, wherein the effective resistance has a value related to an upper cutoff frequency to be tuned by the first filter.

A receiver comprising:

• a first amplifier having an input for receiving a radio frequency signal, and an output;
• a first variable capacitor having a first terminal coupled to the output of the first amplifier, a second terminal coupled to a power supply voltage terminal, and a control terminal for receiving a tuning signal;
• a resistor having a first terminal coupled to the output of the first amplifier, and a second terminal;
• and
• a first inductor having a first terminal coupled to the second terminal of the resistor and a second terminal coupled to the power supply voltage terminal.