verilogA设计

lrr20000830lyl

这是一段用verilogA语言设计的压控振荡器的代码，有人知道标红处的seed是什么意思吗？还有，有大佬知道$rdist_normal的用法吗？

Simon_Z

复制别人写的一段，可以解决你的问题
Normal (Gaussian) Distribution
Use the $rdist_normal function to generate random real numbers (or the $dist_normal
function to generate integer numbers) that are normally distributed. The $rdist_normal
function is not supported in digital contexts.
$rdist_normal ( seed , mean , standard_deviation ) ;
$dist_normal ( seed , mean , standard_deviation ) ;
seed is a scalar integer variable used to initialize the sequence of generated numbers. seed
must be a variable because the function updates the value of seed at each iteration. To
ensure generation of a normal distribution, change the value of seed only when you initialize
the sequence.
mean is an integer or real expression that specifies the value to be approached by the mean
value of the generated numbers.
standard_deviation is an integer or real expression that determines the width of
spread of the generated values around mean. Using a larger standard_deviation
spreads the generated values over a wider range.
To generate a gaussian distribution, use a mean of 0 and a standard_deviation of 1.
For example, the following module returns a series of real numbers that together form a
gaussian distribution.
module distcheck (pinout) ;
electrical pinout ;
integer seed ;
real rrandnum ;
analog begin
@ (initial_step) begin
seed = 23 ;
end
rrandnum = $rdist_normal( seed, 0, 1 ) ;
$display ("Random number is %g", rrandnum ) ;
V(pinout) <+ rrandnum ;
end // of analog block
endmodul

洛神孤恋

seed是产生随机数的种子，指定某个seed后则每次仿真都是同样的随机数序列。$rdist_normal函数用来产生正态分布的随机数序列，输入参数是seed、均值、方差。