Method and apparatus for a frequency agile variable bandwidth transceiver

• US 20060153284A1
• Filed: 01/11/2006
• Published: 07/13/2006
• Est. Priority Date: 08/11/2000
• Status: Abandoned Application

• Current Assignee: Novatel Wireless, Inc. (Inseego Corp.)
• Original Assignee: Novatel Wireless, Inc. (Inseego Corp.)
• Inventors: Souissi, Slim Salah, Andrews, Michael Scott
• Application Number:
  US11/330,400
• Publication Number:
  US 20060153284A1
• Time in Patent Office: Days
• US Class Current: 375/219
• CPC Class Codes: H04B 1/0003 Software-defined radio [SDR] systems, i.e. systems wherein components typically implemented in hardware, e.g. filters or modulators/demodulators, are implented using software, e.g. by involving an AD or DA conversion stage such that at least part of the signal processing is performed in the digital domain digital baseband systems H04L25/00; digital modulation/demodulation H04L27/00; CDMA H04B1/707; TDMA H04B7/2643; image transmission H04N5/00
• CPC Class Codes: H04B 1/0025 using a sampling rate lower than twice the highest frequency component of the sampled signal for demodulation of angle-modulated signals H03D3/006
• CPC Class Codes: H04B 1/1036 with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters H04B1/123 takes precedence; filter circuits H03H
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04B 1/408 the transmitter oscillator frequency being identical to the receiver local oscillator frequency
• CPC Class Codes: H04L 27/1525 using quadrature demodulation

Abstract

A new radio frequency transceiver architecture comprises a combination of direct digital synthesis and digital control functions to control dual switched capacitor filters in order to perform radio frequency conversion directly to and from baseband.

Claims

1. A frequency agile variable bandwidth radio frequency (RF) transceiver comprising:

an RF input/output stage for input of an RF signal from an antenna during a receive mode and for output of an RF signal to an antenna during a transmit mode;

an RF splitter for splitting the input RF input signal into a first RF signal and a second RF signal;

a direct digital synthesis and control (DDS) circuit including a programmable oscillator;

an in-phase component polyphase filter for filtering and bandlimiting said first RF signal under the control of said DDS circuit to generate a first output bandlimited signal;

a quadrature component polyphase filter for filtering said second RF signal under the control of said DDS circuit to generate a second output bandlimited signal; and

a baseband processor for demodulating said first and second output bandlimited signals to generate an output digital signal comprising a plurality of data bits.

2. The RF transceiver of claim 1, wherein said in-phase component polyphase filter comprises a first switched capacitor filter, and wherein said quadrature component polyphase filter comprises a second switched capacitor filter.

3. The RF transceiver of claim 2, wherein said first and second switched capacitor filters operate 90 degrees out of phase from each other, and wherein each said switched capacitor filter includes a mixer element which operates to convert the RF signal to a baseband frequency.

4. The RF transceiver of claim 1, further comprising a third polyphase filter coupled to said baseband processor and said DDS for modulating digital data bits in a transmit mode to generate an output RF signal for coupling to an antenna.

5. The RF transceiver of claim 4, wherein said third polyphase filter comprises a third switched capacitor filter.

6. A frequency agile variable bandwidth radio frequency (RF) transceiver comprising:

an RF input/output stage for input of an RF signal from an antenna during a receive mode and for output of an RF signal to an antenna during a transmit mode;

an RF splitter for splitting the input RF input signal into a first RF signal and a second RF signal;

a direct digital synthesis and control (DDS) circuit including a programmable oscillator;

an in-phase component polyphase switched capacitor filter for filtering and bandlimiting said first RF signal under the control of said DDS circuit to generate a first output bandlimited signal;

a quadrature component polyphase switched capacitor filter for filtering said second RF signal under the control of said DDS circuit to generate a second output bandlimited signal;

a mixer coupled to the output of each said switched capacitor filter and operative to tune the output of said respective filter; and

a baseband processor for demodulating said first and second output bandlimited and tuned signals to generate an output digital signal comprising a plurality of data bits.

7. A frequency agile variable bandwidth radio frequency (RF) transceiver comprising:

an RF input/output stage for input of an RF signal from an antenna during a receive mode and for output of an RF signal to an antenna during a transmit mode;

an RF splitter for splitting the input RF input signal into a first RF signal and a second RF signal;

a direct digital synthesis and control (DDS) circuit including a programmable oscillator;

a first sigma-delta modulator coupled to said first RF signal to bandlimit, translate, and sample said first RF signal under the control of said DDS circuit to generate a first output bandlimited signal;

a second sigma-delta modulator coupled to said second RF signal to bandlimit, translate, and sample said second RF signal under the control of said DDS circuit to generate a second output bandlimited signal; and

a baseband processor for demodulating said first and second output bandlimited and tuned signals to generate an output digital signal comprising a plurality of data bits.

8. A method for generating a frequency agile variable bandwidth radio frequency (RF) transceiver comprising the steps of:

detecting an RF signal from an antenna during a receive mode and for output of an RF signal to an antenna during a transmit mode;

splitting the input RF input signal into a first RF signal and a second RF signal;

filtering and bandlimiting said first RF signal using an in-phase component polyphase filter to generate a first output bandlimited and tuned signal;

filtering said second RF signal using a quadrature component polyphase filter to generate a second output bandlimited and tuned signal; and

demodulating said first and second output bandlimited and tuned signals to generate an output digital signal comprising a plurality of data bits.