Feature/m4i/exact sample rate

[peendebak]

The M4i sample_rate parameter returns the sample rate, but rounded to an integer number of Hz. This PR adds a method to return the exact sample rate.

The original parameter is unchanged and naming is similar to the old parameter.

@astafan8 @jenshnielsen

[codecov]

Codecov Report

Merging #1654 into master will not change coverage.
The diff coverage is n/a.

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  Files         143      143           
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  Hits        11825    11825           
  Misses       5820     5820

[jenshnielsen]

Seems fine to me. Are there chances that the corner cases where this would round the opposite ways and give an off by one error in the divisor

[peendebak]

@jenshnielsen I executed

prev_rate=0
for rate in np.linspace(.005e6, 250e6, 300):
    m4i.sample_rate(rate)
    if prev_rate ==m4i.sample_rate():
        continue
    prev_rate = m4i.sample_rate()
    print(f'sample_rate {m4i.sample_rate()} exact_sample_rate {m4i.exact_sample_rate()}' )

to check. The exact_sample_rate gives the correct values.

[jenshnielsen]

@peendebak Cool thanks