An apparatus for phase locked loop bandwidth expansion comprising: a transmitting device including a PLL, a phase or frequency modulator, and a compensation filter installed in front of the phase or frequency modulator and the PLL, the compensation filter configured to provide a modulated input to the phase or frequency modulator and configured to be programmed with a compensation function having filter coefficients, wherein the filter coefficients are based on programmable coefficients and parameters of the transmitting device that were stored on the transmitting device at a time of manufacture, and wherein the compensation function of the compensation filter ( "Fcomp(s)") is given by: Fcomp s = d 0 ∗ s 3 + s 2 ∗ c 2 + s ∗ c 1 + c 0 c 1 ∗ s 3 + s 2 ∗ a 2 + s ∗ a 1 + a 0 where d 0 = w a 2 c 0 = a ∗ K φ ∗ A ∗ b ∗ K vco N c 1 = K φ ∗ A ∗ b ∗ K vco N c 2 = b a 0 = a ∗ w a 2 a 1 = w a 2 ∗ 2 ∗ a ∗ w a a 2 = 2 ∗ w a + a wherein a frequency response of the PLL combined with the compensation filter is given by: Freq s = w a 2 s 2 + 2 ⁢ ξ ∗ w a ∗ s + w a 2 and wherein a frequency response of the PLL is given by: PLL s = s ∗ c 1 + c 0 s 3 + s 2 ∗ c 2 + s ∗ c 1 + c 0 where s is a Laplace transform operator ( jw), d o, c o, c 1, c 2, a 0, a 1, and a 2 are the filter coefficients, and K φ, K vco, A, N, a, b, and ξ are the programmable coefficients and parameters of the transmitting device such that K φ is the phase detector gain, K vco is the voltage controlled oscillator gain, A is a gain value, N is a variable divider value, a is a "zero", b is a "pole", w a is a wanted bandwidth of the frequency response of the PLL combined with the compensation filter, and ξ is a damping factor. a transmitting device including a PLL, a phase or frequency modulator, and a compensation filter installed in front of the phase or frequency modulator and the PLL, the compensation filter configured to provide a modulated input to the phase or frequency modulator and configured to be programmed with a compensation function having filter coefficients, wherein the filter coefficients are based on programmable coefficients and parameters of the transmitting device that were stored on the transmitting device at a time of manufacture, and wherein the compensation function of the compensation filter ( "Fcomp(s)") is given by: Fcomp s = d 0 ∗ s 3 + s 2 ∗ c 2 + s ∗ c 1 + c 0 c 1 ∗ s 3 + s 2 ∗ a 2 + s ∗ a 1 + a 0 where d 0 = w a 2 c 0 = a ∗ K φ ∗ A ∗ b ∗ K vco N c 1 = K φ ∗ A ∗ b ∗ K vco N c 2 = b a 0 = a ∗ w a 2 a 1 = w a 2 ∗ 2 ∗ a ∗ w a a 2 = 2 ∗ w a + a wherein a frequency response of the PLL combined with the compensation filter is given by: Freq s = w a 2 s 2 + 2 ⁢ ξ ∗ w a ∗ s + w a 2 and wherein a frequency response of the PLL is given by: PLL s = s ∗ c 1 + c 0 s 3 + s 2 ∗ c 2 + s ∗ c 1 + c 0 where s is a Laplace transform operator ( jw), d o, c o, c 1, c 2, a 0, a 1, and a 2 are the filter coefficients, and K φ, K vco, A, N, a, b, and ξ are the programmable coefficients and parameters of the transmitting device such that K φ is the phase detector gain, K vco is the voltage controlled oscillator gain, A is a gain value, N is a variable divider value, a is a "zero", b is a "pole", w a is a wanted bandwidth of the frequency response of the PLL combined with the compensation filter, and ξ is a damping factor.