Carrier less modulator using saw filters
View Patent ↗A system and method of carrier less modulation is described in this disclosure that uses SAW filters as a modulator in addition to their conventional use as filters for band limiting an UWB system. This system and method is primarily designed to be used with any integer cycle, ultra-wide band or impulse type modulation and more particularly is designed to work with a method of modulation named xMax. This technique exploits the impulse response of the SAW filter producing a carrier less impulse radio system with limited bandwidth, low average power, but high peak power.
1. A method of generating a carrier less impulse modulated Radio Frequency signal comprising:
Receiving a carrier less digital signal from a digital encoder data source and applying said carrier less digital signal to the input of an un-switched Band Pass Filter;
using the impulse response of said un-switched Band Pass Filter to generate the carrier less impulse modulated Radio Frequency signal having an impulse for each short pulse inputted by said digital encoder data source and no impulse for an absence of short pulse inputted by said digital encoder data source, without an oscillator or signal generator generating a radio frequency carrier signal, said carrier less impulse modulated Radio Frequency signal having limited bandwidth, low average power, but high peak power; and
matching the impedance of said digital encoder data source to the input impedance of said un-switched Band Pass Filter and matching the impedance of the output of said un-switched Band Pass Filter to other stages of a radio system used for amplifying and transmitting said carrier less impulse modulated Radio Frequency signal, wherein said un-switched Band Pass Filter is a SAW (Surface Acoustic Wave) filter.