Patent ID: 7558484

Claim:
A Ultra-Wide Band (UWB) wireless system, comprising: a central station, which can generate Gaussian light pulses, uses optic components to produce Gaussian light pulse signals, primarily comprised of a gain-switched Fabry-Perot laser diode, tunable filter (TF), Erbium-doped optical fiber amplifier (EDFA) and Mach-Zehnder modulator (MZM), where said Fabry-Perot laser diode generates Gaussian light pulse signals after subjecting to DC bias and RF signal tuning, fast speed bit data are loaded into light pulse by modulator to run bit transmission; a base station, which can generate ultra wide band pulse, receive bit transmission of aforesaid central station, and is primarily comprised of PIN photodiode, first order microwave differentiator and highpass filter, transforming light pulse from central station into Gaussian monocycle pulse signal through PIN photodiode and first order microwave differentiator, and passing highpass filter to produce ultra wide band pulse; wherein the EDFA of the central station acts as external input light source and amplifier of Fabry-Perot laser diode are used to generate light pulse trains, transformed into an electronic pulse train signal by a PIN photodiode (PD), through an amplifier and linear microwave differentiator, to generate ultra-wide band Gaussian monocycle pulse radio signals; wherein the linear microwave differentiator can be a first order microwave differentiator, which can transform short pulse to Gaussian monocycle pulse signal; wherein the first order microwave differentiator utilizes discrete time infinite pulse impact response (IIR) in design, choosing system function as follows, where z −1 is unit time delay: G ⁡ ( z ) = 0.5659 ⁢ 1 - z - 1 1 - 0.1319 ⁢ ⁢ z - 1 after defining the system function of discrete time, the transformation function of transmission line is used to represent equal system function to obtain its circuit length, so it is expressed by means of a transmission line paralleled with a short-circuit fragment, where the transformation function of parallel short-circuit fragment T(z) is shown as follows, where Z b is the characteristic impedance of parallel short-circuit fragment and Z 0 is the reference characteristic impedance; T ⁡ ( z ) = 1 - z - 1 ( 1 + c ) - ( 1 - c ) ⁢ z - 1 , c = Z 0 / 2 ⁢ Z b suppose T(z) equals to G(z), c=0.767 and Z b =Z 0 /1.534, when Z 0 =50Ω, apply the above formula to obtain Z b =32.589Ω, based on this impedance, use 25N Arlon PCB with a thickness of 30 mil (0.762 mm) and a dielectric constant ε r =3.38 to complete the design of first order microwave differentiator.