High performance CMOS radio frequency receiver

A radio frequency receiver, comprising:

• a low noise transconductance amplifier operable to amplify and convert a received voltage of a radio frequency signal to a first current;
• a pulse generator operable to generate pulses from a periodic signal, the pulses having a duty cycle of 35% or less;
• a double balanced mixer operable to combine the first current with the pulses to produce a second current, the second current comprising an intermediate frequency signal;
• and
• a direct coupled complex filter operable to filter the second current to a filtered analog signal,
• where the pulses comprise in-phase pulses and quadrature pulses, and the pulse generator comprises a first latch operable to generate the quadrature pulses and a first latch output based on the periodic signal and a second latch output, and a second latch operable to generate the in-phase pulses and the second latch output based on the periodic signal and the first latch output.

A method of receiving a radio frequency signal, comprising:

• converting and amplifying a voltage of the radio frequency signal to a first current;
• generating pulses from a periodic signal, the pulses having a duty cycle of 35% or less;
• reducing overlap of the pulses;
• mixing the first current with the pulses to produce a second current, the second current comprising an intermediate frequency signal;
• and
• filtering the second current to a filtered analog signal;
• where reducing the overlap of the pulses comprises correcting a crossover threshold of the pulses, and where:
• the pulses comprise in-phase pulses and quadrature pulses;
• correcting the crossover threshold comprises selecting a crossing point of the in-phase pulses and the quadrature pulses to reduce the amount of time the in-phase pulses and quadrature pulses are simultaneously active;
• and
• the intermediate frequency signal comprises an in-phase signal and a quadrature signal.

A method of receiving a radio frequency signal, comprising:

• converting and amplifying a voltage of the radio frequency signal to a first current;
• generating pulses from a periodic signal, the pulses having a duty cycle of 35% or less;
• mixing the first current with the pulses to produce a second current, the second current comprising an intermediate frequency signal;
• and
• filtering the second current to a filtered analog signal,
• where the pulses comprise in-phase pulses and quadrature pulses, and generating pulses comprises generating the quadrature pulses and a first latch output based on the periodic signal and a second latch output, and generating the in-phase pulses and the second latch output based on the periodic signal and the first latch output.

An analog front end of a radio frequency receiver, comprising:

• a low noise amplifier operable to amplify and convert a received voltage of a radio frequency signal to a first current, the low noise amplifier configured to step weight and binary weight the amplification;
• a pulse generator operable to generate in-phase and quadrature pulses based on a periodic signal, the in-phase and quadrature pulses having an approximately 25% duty cycle and comprising a first pulse zero degrees out of phase from the periodic signal, a second pulse one hundred eighty degrees out of phase from the periodic signal, a third pulse ninety degrees out of phase from the periodic signal, and a fourth pulse two hundred seventy degrees out of phase from the periodic signal;
• a crossover correction circuit to reduce overlap of the in-phase and quadrature pulses;
• and
• a mixer operable to combine the first current with the in-phase and quadrature pulses to produce a second current, the second current comprising an intermediate frequency signal;
• where:
• the crossover correction circuit is operable to control an amplitude crossover threshold of the in-phase and quadrature pulses, such that the in-phase and quadrature pulses are not active simultaneously;
• and
• the analog front end further comprises a direct coupled complex filter operable to filter the intermediate frequency signal to a filtered analog signal.

A radio frequency receiver, comprising:

• a low noise transconductance amplifier operable to amplify and convert a received voltage of a radio frequency signal to a first current;
• a pulse generator operable to generate pulses from a periodic signal, the pulses having a duty cycle of 35% or less;
• a crossover correction circuit to reduce overlap of the pulses;
• a double balanced mixer operable to combine the first current with the pulses to produce a second current, the second current comprising an intermediate frequency signal;
• and
• a direct coupled complex filter operable to filter the second current to a filtered analog signal;
• an active bias generation circuit configured to bias the amplifier such that low frequency bias noise in the radio frequency signal is inhibited in the presence of large blocking signals;
• where the active bias generation circuit comprises a reference current source coupled to a supply voltage and a node;
• a first NMOS transistor with a source coupled to ground, a drain coupled to the node, and a gate coupled to the received voltage;
• and a second NMOS transistor with a source coupled to the received voltage, a drain coupled to the supply voltage, and a gate coupled to the node.