step
System object: twoRayChannel
Syntax
prop_sig = step(channel,sig,origin_pos,dest_pos,origin_vel,dest_vel)
Description
Note
Starting in R2016b, instead of using the step
method to
perform the operation defined by the System object™, you can call the object with arguments, as if it were a function. For example,
y = step(obj,x)
and y = obj(x)
perform equivalent
operations.
returns the resulting signal, prop_sig
= step(channel
,sig
,origin_pos
,dest_pos
,origin_vel
,dest_vel
)prop_sig
, when a narrowband signal,
sig
, propagates through a two-ray channel from the
origin_pos
position to the dest_pos
position. Either
the origin_pos
or dest_pos
arguments can have multiple
points but you cannot specify both as having multiple points. The velocity of the signal origin
is specified in origin_vel
and the velocity of the signal destination is
specified in dest_vel
. The dimensions of origin_vel
and
dest_vel
must agree with the dimensions of origin_pos
and dest_pos
, respectively.
Electromagnetic fields propagated through a two-ray channel can be polarized or
nonpolarized. For, nonpolarized fields, such as an acoustic field, the propagating signal field,
sig
, is a vector or matrix. When the fields are polarized,
sig
is an array of structures. Every structure element represents an
electric field vector in Cartesian form.
In the two-ray environment, there are two signal paths connecting every signal origin and destination pair. For N signal origins (or N signal destinations), there are 2N number of paths. The signals for each origin-destination pair do not have to be related. The signals along the two paths for any single source-destination pair can also differ due to phase or amplitude differences.
You can keep the two signals at the destination separate or
combined — controlled by the CombinedRaysOutput
property. Combined means that the signals at the source propagate separately
along the two paths but are coherently summed at the destination into a single quantity. To use
the separate option, set CombinedRaysOutput
to
false
. To use the combined option, set
CombinedRaysOutput
to true
. This option is convenient
when the difference between the sensor or array gains in the directions of the two paths is not
significant and need not be taken into account.
Note
The object performs an initialization the first time the object is executed. This
initialization locks nontunable properties
and input specifications, such as dimensions, complexity, and data type of the input data.
If you change a nontunable property or an input specification, the System object issues an error. To change nontunable properties or inputs, you must first
call the release
method to unlock the object.
Input Arguments
Output Arguments
Examples
References
[1] Proakis, J. Digital Communications. New York: McGraw-Hill, 2001.
[2] Skolnik, M. Introduction to Radar Systems, 3rd Ed. New York: McGraw-Hill
[3] Saakian, A.Radio Wave Propagation Fundamentals. Norwood, MA: Artech House, 2011.
[4] Balanis, C.Advanced Engineering Electromagnetics. New York: Wiley & Sons, 1989.
[5] Rappaport, T.Wireless Communications: Principles and Practice, 2nd Ed New York: Prentice Hall, 2002.
Extended Capabilities
Version History
Introduced in R2021a