Apparatus For Coupling A Wireless Communication Device To A Physical Device

Abstract

A wireless communication device may be configured to transmit and receive data through a physical device, such as a cable. Relatively higher transmit radio frequency (RF) signals from the wireless communication device may be shifted to a relatively lower frequency, thereby enabling the relatively lower frequency signals to be carried by the physical device. Similarly, relatively lower frequency signals from the physical device may be shifted to relatively higher frequencies, thereby enabling the wireless communication device to receive the signals from the physical device. In one embodiment, the frequency of the RF signals may be between 2.3 and 2.7 GHz and the frequency of the relatively lower frequency shifted signals may be between 900 and 1100 MHz.

1 . An external data transceiver for coupling between a wireless communication device and a physical device, the external data transceiver comprising:
 a transmit circuit for frequency shifting a received signal having a first frequency from the wireless communication device to a second frequency receivable by the physical device;   a receive circuit for frequency shifting a received signal having a third frequency from the physical device to a fourth frequency receivable by the wireless communication device; and   a switch for selectively coupling one of the transmit circuit and the receive circuit to the physical device,   wherein the receive circuit includes:   a low noise amplifier (LNA) for amplifying the received signal from the physical device via the switch;   a first band-pass filter for filtering an amplified signal from the LNA;   an attenuator for receiving an output of the first band-pass filter;   a receive mixer for mixing a filtered and attenuated signal from the attenuator with a local oscillator signal, thereby generating a fourth frequency signal;   a second band-pass filter for filtering the fourth frequency signal and providing an output to the wireless communication device.   
     
     
         2 . A method for allowing communication between a wireless communication device and a physical device, the method comprising:
 frequency shifting a received signal having a first frequency from the wireless communication device to a second frequency receivable by the physical device; and   frequency shifting a received signal having a third frequency from the physical device to a fourth frequency receivable by the wireless communication device; and   selectively allowing one of frequency shifting from the wireless communication device to the physical device and frequency shifting from the physical device to the wireless communication device,   wherein frequency shifting the received signal having the third frequency from the physical device to the fourth frequency receivable by the wireless communication device includes:   amplifying the received signal from the physical device, thereby generating an amplified signal;   filtering the amplified signal, thereby generating a first filtered signal;   attenuating the first filtered signal to generate an attenuated first filtered signal;   mixing the attenuated first filtered signal with a local oscillator signal, thereby generating a fourth frequency signal;   filtering the fourth frequency signal, thereby generating a second filtered signal; and   providing the second filtered signal to the wireless communication device.   
     
     
         3 . The external data transceiver of  claim 1 , wherein the LNA increases the received signal with a gain of approximately 20 dB. 
     
     
         4 . The external data transceiver of  claim 1 , wherein the LNA is implemented with a bipolar transistor. 
     
     
         5 . The external data transceiver of  claim 1 , wherein first band-pass filter has a pass band between 900 and 1100 MHz. 
     
     
         6 . The external data transceiver of  claim 5 , wherein the first band-pass filter has −10 dB of attenuation at frequencies at and below 800 MHz, and −20 dB of attenuation at frequencies at and above 1300 MHz. 
     
     
         7 . The external data transceiver of  claim 1 , wherein the first band-pass filter is implemented by an elliptic filter. 
     
     
         8 . The external data transceiver of  claim 1 , wherein the attenuator is configured to reduce an amplitude of an output of the first band-pass filter. 
     
     
         9 . The external data transceiver of  claim 8 , further including bypass circuitry for bypassing the attenuator. 
     
     
         10 . The external data transceiver of  claim 1 , wherein the receive mixer shifts a frequency of the filtered signal from 900-1100 MHz to 2.3-2.7 MHz. 
     
     
         11 . The external data transceiver of  claim 1 , wherein the receive mixer is implemented as an active mixer based on a bipolar transistor. 
     
     
         12 . The external data transceiver of  claim 1 , wherein the receive mixer is implemented with primarily passive components. 
     
     
         13 . The external data transceiver of  claim 1 , wherein second band-pass filter has a pass band between 2.3 to 2.6 GHz. 
     
     
         14 . The external data transceiver of  claim 13 , wherein the second band-pass filter has −30 dB of attenuation at frequencies at and below 1.6 GHz, and −30 dB of attenuation at frequencies at and above 3.2 GHz. 
     
     
         15 . The external data transceiver of  claim 1 , wherein the second band-pass filter is implemented by a printed-circuit comb filter. 
     
     
         16 . The method of  claim 2 , wherein attenuating the first filtered signal includes selectively turning off attenuation, which then converts the attenuated first filtered signal into the first filtered signal.