1. A method to facilitate docking a trailer to a vehicle comprising:
(a) placing an inflexible, fixed marker member permanently secured to a magnetic mounting member substantially adjacent to a hitch ball on said mounting member; and
(b) viewing said marker member from the vehicle as the vehicle is docked with said trailer.
2. A method to facilitate maneuvering a trailer coupled to a vehicle comprising:
(a) placing an inflexible, fixed marker member permanently secured to a magnetic mounting member to a metal portion of a trailer;
(b) viewing said marker member from the vehicle while maneuvering the trailer coupled to the vehicle.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A converter of a digital signal into a pulse-width modulated signal, comprising:
a first conversion unit receiving, at a first frequency, successive digital signals each having one of a first determined number of values, and providing first intermediary signals, at the first frequency, each having one of a second determined number of values smaller than the first determined number;
a unit performing a decimation of the first intermediary signals to provide second intermediary signals at a second frequency equal to the first frequency divided by the second determined number minus one; and
a second conversion unit providing at the second frequency, from the second intermediary signals, a two-state pulse-width modulated signal having a minimum duration in one of the two states which is equal to the inverse of the first frequency, the first conversion unit receiving said pulse-width modulated signal.
2. The converter of claim 1, wherein the second conversion unit is capable of providing, for an alternation of even and odd cycles at the first frequency, the pulse-width modulated signal such that, on each even cycle, the pulse-width modulated signal comprises at most one falling edge and comprises no rising edge and, on each odd cycle, the pulse-width modulated signal comprises at most one rising edge and comprises no falling edge.
3. The converter of claim 1, wherein the first conversion unit is capable of performing a filtering on the difference between the successive digital signals and the pulse-width modulated signal.
4. The converter of claim 1, wherein the first conversion unit is capable of providing the first intermediary signals in digital form.
5. The converter of claim 1, further comprising a class-D amplifier controlled by the pulse-width modulated signal.
6. A method of conversion of a digital signal into a pulse-width modulated signal comprising the steps of:
receiving, at a first frequency, successive digital signals each having one of a first determined number of values;
providing at the first frequency, from the successive digital signals, first intermediary signals each having one of a second determined number of values smaller than the first determined number;
performing a decimation of the first intermediary signals to provide second intermediary signals at a second frequency equal to the first frequency divided by the second determined number minus one; and
providing at the second frequency, from the second intermediary signals, a two-state pulse-width modulated signal having a minimum duration in one of its two states equal to the inverse of the first frequency, the first intermediary signals being also provided from said pulse-width modulated signal.
7. The method of claim 6, wherein the pulse-width modulated signal is provided on an alternation of even and odd cycles at the first frequency, such that, on each even cycle, the pulse-width modulated signal comprises at most one falling edge and comprises no rising edge and, on each odd cycle, the pulse-width modulated signal comprises at most one rising edge and comprises no falling edge.
8. The method of claim 6, wherein the first intermediary signals are provided from a filtering of the difference between the successive digital signals and the pulse-width modulated signal.
9. The method of claim 6, wherein the first and second intermediary signals are digital signals.
10. The method of claim 6, further comprising the step of controlling a class-D amplifier with the pulse-width modulated signal.