Front end filter circuitry for a dual band GSM/DCS cellular phone
First Claim
Patent Images
1. A radio frequency circuit comprising:
- a high-pass filter receiving an RF signal;
a first SAW filter having an input connected to the high-pass filter;
a first amplifier connected to the output of the first SAW filter;
a second SAW filter receiving an RF signal;
a second amplifier connected to the output of the second SAW filter;
a combiner for combining the outputs of the first and second amplifier to form an output signal; and
a single side band mixer having an input connected to the combiner to receive the output signal.
9 Assignments
0 Petitions
Accused Products
Abstract
A front end circuit for an RF dual band GSM/DCS phone includes a first channel including an elliptical high-pass filter, a first SAW filter, and a low noise amplifier and a second channel including a second SAW filter and a second low noise amplifier. The output of each channel is alternately switchable to a single-side band mixer circuit. This front end circuit arrangement provides significantly reduced cost and part count over other approaches.
122 Citations
25 Claims
-
1. A radio frequency circuit comprising:
-
a high-pass filter receiving an RF signal; a first SAW filter having an input connected to the high-pass filter; a first amplifier connected to the output of the first SAW filter; a second SAW filter receiving an RF signal; a second amplifier connected to the output of the second SAW filter; a combiner for combining the outputs of the first and second amplifier to form an output signal; and a single side band mixer having an input connected to the combiner to receive the output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
-
-
16. A front end radio frequency receiver comprising:
-
a high-pass filter; a first SAW filter having an input connected to the high-pass filter; and a mixer having an input connected to the output of the first SAW filter, wherein the mixer suppresses a frequency component consisting of a local oscillator frequency minus an IF frequency, and the high-pass filter provides compensation for insufficient side band suppression by the mixer. - View Dependent Claims (17, 18, 19, 20, 21)
-
-
22. A method for down-converting a dual band radio frequency (RF) signal comprising the steps of:
-
filtering a first RF signal with a high-pass filter and a first SAW filter; filtering a second RF signal with a second SAW filter; amplifying the first and second RF signal; combining the first and second RF signal to form an output signal; and mixing the output signal and a local oscillator signal with a single-side band mixer. - View Dependent Claims (23, 24)
-
-
25. A method for down-converting a dual band radio frequency (RF) signal in a DCS frequency channel comprising the steps of:
-
filtering an RF signal with a high-pass filter and a first SAW filter; providing compensation for insufficient side band suppression in the RF signal; and mixing the RF signal and a local oscillator signal with a single-side band mixer, wherein the mixing step further comprises the step of suppressing a frequency component consisting of a local oscillator frequency minus an IF frequency.
-
Specification