  The pulse profile of PSR B1133+16 is usually regarded as a conal-double
structure. However, its multifrequency profiles cannot simply be fitted with
two Gaussian functions, and a third component is always needed to fit the
bridge region (between two peaks). This would introduce additional, redundant
parameters. In this paper, through a comparison of five fitting functions
(Gaussian, von Mises, hyperbolic secant, square hyperbolic secant, and
Lorentz), it is found that the square hyperbolic secant function can best
reproduce the profile, yielding an improved fit. Moreover, a symmetric 2D
radiation beam function, instead of a simple 1D Gaussian function, is used to
fit the profile. Each profile with either well-resolved or not-so-well-resolved
peaks could be fitted adequately using this beam function, and the bridge
emission between the two peaks does not need to be a new component. Adopting
inclination and impact angles based on polarization measurements, the opening
angle ({\theta}_{\mu}0) of the radiation beam in a certain frequency band is
derived from beam-function fitting. The corresponding radiation altitudes are
then calculated. Based on multi-frequency profiles, we also computed the
Lorentz factors of the particles and their dispersion at those locations in
both the curvature-radiation (CR) and inverse-Compton-scattering (ICS) models.
We found that the Lorentz factors of the particles decrease rapidly as the
radiation altitude increases. Besides, the radiation prefers to be generated in
annular region rather than core region, and this needs further validation.
