Multiple band RF transmitters and receivers having independently variable RF and IF local oscillators and independent high-side and low-side RF local oscillators

Abstract

Multistage RF transmitter and receiver circuits may use independently variable RF and IF local oscillators, allowing the RF and IF local oscillator frequencies for a given RF channel to be selected to have a large common factor with respect to the reference oscillator used by the local oscillator circuits, thus allowing the use of small divisor numbers in the local oscillator circuits and reducing phase noise. Independent high-side and low-side RF local oscillators may be provided and selectively used depending on the RF channel to be transmitted or received.

1 . A receiver circuit for down-converting a radio frequency (RF) signal, comprising: 
 an RF mixer that down-converts an RF signal to an intermediate frequency (IF) signal;    a first variable frequency RF local oscillator that supplies a first RF local oscillator frequency to the RF mixer;    an IF mixer that down-converts the IF signal to a baseband signal; and    a variable frequency IF local oscillator that supplies an IF local oscillator frequency to the IF mixer, the IF local oscillator frequency being variable independently of variations of the first RF local oscillator frequency.    
   
   
       2 . The circuit claimed in  claim 1 , further comprising a local oscillator control circuit that sets the first RF local oscillator frequency and the IF local oscillator frequency in accordance with an RF channel to be down-converted.  
   
   
       3 . The circuit claimed in  claim 2 , further comprising a local oscillator configuration table referenced by the local oscillator control circuit to set the first RF local oscillator frequency and IF local oscillator frequency, the configuration table storing data indicating RF local oscillator configurations and IF local oscillator configurations corresponding to respective RF channels.  
   
   
       4 .- 7 . (canceled)  
   
   
       8 . An integrated circuit chip embodying the receiver circuit of  claim 1 .  
   
   
       9 . An RF communication device embodying the receiver circuit of  claim 1 .  
   
   
       10 . A transmitter circuit for producing a radio frequency (RF) signal, comprising: 
 an IF mixer that up-converts a baseband signal to an intermediate frequency (IF) signal;    a variable frequency IF local oscillator that supplies an IF local oscillator frequency to the IF mixer;    an RF mixer that up-converts the intermediate frequency (IF) signal to an RF signal; and    a first variable frequency RF local oscillator that supplies a first RF local oscillator frequency to the RF mixer,    the IF local oscillator frequency being variable independently of variations of the first RF local oscillator frequency.    
   
   
       11 . The circuit claimed in  claim 10 , further comprising a local oscillator control circuit that sets the first RF local oscillator frequency and the IF local oscillator frequency in accordance with an RF channel to be transmitted.  
   
   
       12 . The circuit claimed in  claim 11 , further comprising a local oscillator configuration table referenced by the local oscillator control circuit to set the first RF local oscillator frequency and IF local oscillator frequency, the configuration table storing data indicating RF local oscillator configurations and IF local oscillator configurations corresponding to respective RF channels.  
   
   
       13 .- 16 . (canceled)  
   
   
       17 . An integrated circuit chip embodying the transmitter circuit of  claim 10 .  
   
   
       18 . An RF communication device embodying the transmitter circuit of  claim 10 .  
   
   
       19 . A transceiver circuit for radio frequency (RF) communications, comprising: 
 an RF receiver mixer that down-converts an RF received signal to an intermediate frequency (IF) received signal;    an IF receiver mixer that down-converts the IF received signal to a baseband received signal;    an IF transmit mixer that up-converts a baseband transmit signal to an IF transmit signal;    an RF transmit mixer that up-converts the IF transmit signal to an RF transmit signal;    a first variable frequency RF local oscillator that supplies a first RF local oscillator frequency to the RF receiver mixer and the RF transmit mixer; and    a variable frequency IF local oscillator that supplies an IF local oscillator frequency to the IF receiver mixer and the IF transmit mixer, the IF local oscillator frequency being variable independently of variations of the first RF local oscillator frequency.    
   
   
       20 . The circuit claimed in  claim 19 , further comprising a local oscillator control circuit that sets the first RF local oscillator frequency and the IF local oscillator frequency in accordance with an RF channel to be transmitted and received.  
   
   
       21 . The circuit claimed in  claim 20 , further comprising a local oscillator configuration table referenced by the local oscillator control circuit to set the first RF local oscillator frequency and IF local oscillator frequency, the configuration table storing data indicating RF local oscillator configurations and IF local oscillator configurations corresponding to respective RF channels.  
   
   
       22 .- 25 . (canceled)  
   
   
       26 . An integrated circuit chip embodying the transceiver circuit of  claim 19 .  
   
   
       27 . An RF communication device embodying the transceiver circuit of  claim 19 .  
   
   
       28 . A radio frequency (RF) receiver circuit comprising: 
 an RF mixer that down-converts a received RF signal;    a first variable frequency RF local oscillator that supplies a first RF local oscillator frequency;    a second variable frequency RF local oscillator that supplies a second RF local oscillator frequency; and    a local oscillator control circuit that selectively controls the first variable frequency RF local oscillator and the second variable frequency RF local oscillator to supply a low-side local oscillator signal from the first variable frequency RF local oscillator to the RF mixer or a high-side local oscillator signal from the second variable frequency RF local oscillator to the RF mixer in accordance with an RF channel to be down-converted.    
   
   
       29 . The circuit claimed in  claim 28 , wherein the local oscillator control circuit controls the first variable frequency RF local oscillator and the second variable frequency RF local oscillator to supply a low-side local oscillator signal for down-converting channels of the 802.11a standard in the range of 5.18 GHz to 5.32 GHz and to supply a high-side local oscillator signal for down-converting channels of the 802.11 a standard in the range of 5.745 GHz to 5.805 GHz.  
   
   
       30 . The circuit claimed in  claim 28 , further comprising a local oscillator configuration table referenced by the local oscillator control circuit to control the first variable frequency RF local oscillator and the second variable frequency RF local oscillator, the configuration table storing data indicating RF local oscillator configurations corresponding to respective RF channels.  
   
   
       31 . The circuit claimed in  claim 28 , wherein the first variable frequency RF local oscillator and the second variable frequency RF local oscillator are implemented as a phase locked loop comprising a first voltage controlled oscillator producing the first RF local oscillator frequency and a second voltage controlled oscillator producing the second RF local oscillator frequency.  
   
   
       32 . The circuit claimed in  claim 28 , wherein the RF mixer converts the RF signal to an intermediate frequency (IF) signal, 
 wherein the receiver circuit further comprises: 
 an IF mixer that down-converts the IF signal to a baseband signal; and  
 a variable frequency IF local oscillator that supplies an IF local oscillator frequency to the IF mixer, the IF local oscillator frequency being variable independently of variations of the first RF local oscillator frequency and the second RF local oscillator frequency, and  
   wherein the local oscillator control circuit sets the IF local oscillator frequency of the variable frequency IF local oscillator in accordance with an RF channel to be down-converted.    
   
   
       33 . An integrated circuit chip embodying the receiver circuit of  claim 28 .  
   
   
       34 . An RF communication device embodying the receiver circuit of  claim 28 .  
   
   
       35 . A radio frequency (RF) transmitter circuit comprising: 
 an RF mixer that up-converts a signal to an RF frequency;    a first variable frequency RF local oscillator that supplies a first RF local oscillator frequency;    a second variable frequency RF local oscillator that supplies a second RF local oscillator frequency; and    a local oscillator control circuit that selectively controls the first variable frequency RF local oscillator and the second variable frequency RF local oscillator to supply a low-side local oscillator signal from the first variable frequency RF local oscillator to the RF mixer or a high-side local oscillator signal from the second variable frequency RF local oscillator to the RF mixer in accordance with an RF channel to be transmitted.    
   
   
       36 . The circuit claimed in  claim 35 , wherein the local oscillator control circuit controls the first variable frequency RF local oscillator and the second variable frequency RF local oscillator to supply a low-side local oscillator signal for up-converting to channels of the 802.11a standard in the range of 5.18 GHz to 5.32 GHz and to supply a high-side local oscillator signal for up-converting to channels of the 802.11a standard in the range of 5.745 GHz to 5.805 GHz.  
   
   
       37 . The circuit claimed in  claim 35 , further comprising a local oscillator configuration table referenced by the local oscillator control circuit to control the first variable frequency RF local oscillator and the second variable frequency RF local oscillator, the configuration table storing data indicating RF local oscillator configurations corresponding to respective RF channels.  
   
   
       38 . The circuit claimed in  claim 35 , wherein the first variable frequency RF local oscillator and the second variable frequency RF local oscillator are implemented as a phase locked loop comprising a first voltage controlled oscillator producing the first RF local oscillator frequency and a second voltage controlled oscillator producing the second RF local oscillator frequency.  
   
   
       39 . The circuit claimed in  claim 35 , wherein the RF mixer up-converts an intermediate frequency (IF) signal to an RF signal, 
 wherein the transmitter circuit further comprises: 
 an IF mixer that up-converts a baseband signal to the IF signal; and  
 a variable frequency IF local oscillator that supplies an IF local oscillator frequency to the IF mixer, the IF local oscillator frequency being variable independently of variations of the first RF local oscillator frequency and the second RF local oscillator frequency, and  
   wherein the local oscillator control circuit sets the IF local oscillator frequency of the variable frequency IF local oscillator in accordance with an RF channel to be transmitted.    
   
   
       40 . An integrated circuit chip embodying the transmitter circuit of  claim 35 .  
   
   
       41 . An RF communication device embodying the transmitter circuit of  claim 35 .  
   
   
       42 . A radio frequency (RF) transceiver circuit comprising: 
 an RF receiver mixer that down-converts a received RF signal;    an RF transmit mixer that up-converts a transmit signal to an RF transmit signal;    a first variable frequency RF local oscillator that supplies a first RF local oscillator frequency;    a second variable frequency RF local oscillator that supplies a second RF local oscillator frequency; and    a local oscillator control circuit that selectively controls the first variable frequency RF local oscillator and the second variable frequency RF local oscillator to supply a low-side local oscillator signal from the first variable frequency RF local oscillator to the RF receiver mixer and the RF transmit mixer or a high-side local oscillator signal from the second variable frequency RF local oscillator to the RF receiver mixer and the RF transmit mixer in accordance with an RF channel to be received and transmitted.    
   
   
       43 . The circuit claimed in  claim 42 , wherein the local oscillator control circuit controls the first variable frequency RF local oscillator and the second variable frequency RF local oscillator to supply a low-side local oscillator signal for receiving and transmitting channels of the 802.11a standard in the range of 5.18 GHz to 5.32 GHz and to supply a high-side local oscillator signal for receiving and transmitting channels of the 802.11a standard in the range of 5.745 GHz to 5.805 GHz.  
   
   
       44 . The circuit claimed in  claim 42 , further comprising a local oscillator configuration table referenced by the local oscillator control circuit to control the first variable frequency RF local oscillator and the second variable frequency RF local oscillator, the configuration table storing data indicating RF local oscillator configurations corresponding to respective RF channels.  
   
   
       45 . The circuit claimed in  claim 42 , wherein the first variable frequency RF local oscillator and the second variable frequency RF local oscillator are implemented as a phase locked loop comprising a first voltage controlled oscillator producing the first RF local oscillator signal frequency and a second voltage controlled oscillator producing the second RF local oscillator frequency.  
   
   
       46 . The circuit claimed in  claim 42 , wherein the RF receiver mixer down-converts an RF received signal to an intermediate frequency (IF) received signal, 
 wherein the RF transmit mixer up-converts an intermediate frequency (IF) signal to the RF transmit signal,    wherein the transceiver circuit further comprises: 
 an IF receiver mixer that down-converts the IF received signal to a baseband received signal;  
 an IF transmit mixer that up-converts a baseband transmit signal to the IF transmit signal; and  
 a variable frequency IF local oscillator that supplies an IF local oscillator frequency to the IF receiver mixer and the IF transmit mixer, the IF local oscillator frequency being variable independently of variations of the first RF local oscillator frequency and the second RF local oscillator frequency, and  
   wherein the local oscillator control circuit sets the IF local oscillator frequency of the variable frequency IF local oscillator in accordance with an RF channel to be received and transmitted.    
   
   
       47 . An integrated circuit chip embodying the transceiver circuit of  claim 42 .  
   
   
       48 . An RF communication device embodying the transceiver circuit of  claim 42 .  
   
   
       49 . A method of operating a radio frequency (RF) transceiver circuit, comprising: 
 receiving a signal indicating an RF channel to transmit or receive;    obtaining RF local oscillator configuration data and intermediate frequency (IF) local oscillator configuration data for the RF channel from a table containing local oscillator configuration data for respective RF channels;    setting an RF local oscillator to produce an RF local oscillator frequency in accordance with said obtained RF local oscillator configuration data; and    setting an IF local oscillator to produce an IF local oscillator frequency in accordance with said obtained IF local oscillator configuration data.    
   
   
       50 . A method of operating a radio frequency (RF) transceiver circuit, comprising: 
 receiving a signal indicating an RF channel to transmit or receive; and    selectively providing one of a high-side RF local oscillator signal and a low-side RF local oscillator signal to an RF mixer in accordance with the RF channel to up-convert or down-convert the RF channel.