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simulator.oldsetnoise - Function

2.4.1 Set the noise level fixed sigma (mode=simplenoise) or Brown’s equation (mode=calculate) OBSOLETE VERSION


Description

Set various system parameters from which the thermal (ie, random additive) noise level will be calculated.

For mode=simplenoise, one specifies the standard deviation for the noise to be added to real and imaginary parts of the visibility.

For mode=calculate, the noise will vary with dish diameter, antenna efficiency, system temperature, opacity, sky temperature, etc. The noise will increase with the airmass if tau is greater than zero. The noise is calculated according to the Brown Equation (ie, R.L. Brown’s calculation of MMA sensitivity, 3Oct95):

       √-
      4-2[TrxeτA-+-Tatm-(eτA---ϵl)-+Tcmb]-
ΔS  =          ϵqϵaπD2 √Δ-νΔt
(2.16)

Arguments





Inputs

mode

Mode of operation. String: ’simplenoise’—’calculate’

allowed:

string

Default:

calculate

’simplenoise’

’calculate’

table

Name of noise table - not currently implemented

allowed:

string

Default:

simplenoise

Level of noise (if mode=simplenoise)

allowed:

any

Default:

variant 0.0Jy

antefficiency

antenna efficiency

allowed:

double

Default:

0.8

0.8

correfficiency

Correlation efficiency

allowed:

double

Default:

0.85

0.85

spillefficiency

Forward spillover efficiency

allowed:

double

Default:

0.85

0.85

tau

Atmospheric Opacity

allowed:

double

Default:

0.1

0.1

trx

Receiver temp (ie, all non-atmospheric Tsys contributions) [K]

allowed:

double

Default:

50

50

tatmos

(Physical, not Brightness) Temperature of atmosphere [K]

allowed:

double

Default:

230.0

230.0

tcmb

Temperature of cosmic microwave background [K]

allowed:

double

Default:

2.7

2.7

Returns
bool
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