US 5,852,784 A · Multiband mobile unit communication apparatus

Abstract

A multiband mobile unit communication apparatus is disclosed which comprises: an antenna for receiving 1st and 2nd bands of radio wave SIGs including quadrature modulation SIGs; a 1st LO CKT for generating a 1st LO SIG; 1st and 2nd receiving CKTs for generating 1st and 2nd IF SIGs from the 1st and 2nd bands of radio wave SIGs using the 1st LO SIG respectively; a switching CKT responsive to a switching control SIG indicative of 1st and 2nd modes for outputting the 1st IF SIG in the 1st mode and outputting the 2nd IF SIG in the 2nd mode; a 2nd LO CKT for generating 2nd and 3rd LO SIGs in the 1st and 2nd modes respectively; and a quadrature demodulation CKT for demodulating and outputting quadrature SIGs from an output from the switching CKT using the 2nd and third LO SIGs in the 1st and 2nd modes respectively. The 2nd LO CKT comprises: a local oscillator for generating a 4th LO SIG, a FRQ divider for dividing the 4th LO SIG with a given divisor and generating the 2nd LO SIG; and a switch for outputting the 2nd LO SIG in the 1st mode and outputting the 4th LO SIG as the 3rd LO SIG in the 2nd mode in response to the switching control SIG. The given divisor corresponds to a ratio between center FRQs of the 1st and 2nd IF SIGs. The 2nd LO CKT may change the LO FRQ by switchably connecting resonating elements to an oscillator.

Claims12

Dependent claims

A multiband mobile unit communication apparatus comprising:

an antenna for receiving multiple frequency bands of radio wave signals;
a first local oscillation circuit for generating a first local oscillation signal corresponding to said multiple frequency bands of radio wave signals;
receiving circuits corresponding to said multiple frequency bands of radio wave signals for generating intermediate frequency signals corresponding to said multiple frequency bands by mixing said multiple frequency bands of radio wave signals with said first local oscillation signal corresponding to said multiple frequency bands respectively;
switching means responsive to a switching control signal indicative of which frequency bands the mobile unit is operating for outputting one of said intermediate frequency signals according to the mobile communication system using different frequency bands of radio wave signals;
a second local oscillation circuit for generating the second local oscillation signals corresponding to said multiple frequency bands and for switching the output from said second local oscillation circuit responsive to said switching control signal;
and
a quadrature demodulation means for demodulating and outputting baseband signals by mixing an output from said switching means with said second local oscillation signals that is switched by said switching control signal.

4 more elements

Dependencies are inferred from the claim text.

Multiband mobile unit communication apparatus

Life of this patent

Multiband mobile unit communication apparatus

Life of this patent

Abstract

Claims12