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measures.frequency - Function

1.4.1 define a frequency measure


Description

frequency defines a frequency measure from the CLI. It has to specify a reference code, frequency quantity value (see introduction for the action on a scalar quantity with either a vector or scalar value),

and optionally it can specify an offset, which in itself has to be a frequency. Allowable reference codes are: REST LSRK LSRD BARY GEO TOPO GALACTO LGROUP CMB.
Note that additional ones may become available. Check in CASA with:

print "\t----\t frequency Ex 1 \t----"  
print me.listcodes(me.frequency())  
#{’normal’: [’REST’, ’LSRK’, ’LSRD’, ’BARY’, ’GEO’, ’TOPO’,  
# ’GALACTO’, ’LGROUP’, ’CMB’], ’extra’: []}

The frequency quantity values should be in one of the recognised units (examples all give same frequency):

Arguments





Inputs

rf

reference code

allowed:

string

Default:

LSRK

v0

frequency/wavelength/…

allowed:

any

Default:

variant

off

optional offset frequency measure

allowed:

record

Default:

Returns
record

Example

 
 
print "\t----\t frequency Ex 2 \t----"  
print me.frequency(’lsrk’,’5GHz’)  
#{’m0’: {’value’: 5000000000.0, ’unit’: ’Hz’},  
# ’refer’: ’LSRK’,  
# ’type’: ’frequency’}  
print me.frequency(’lsrk’,’21cm’)  
#{’m0’: {’value’: 1427583133.3333333, ’unit’: ’Hz’},  
# ’refer’: ’LSRK’,  
# ’type’: ’frequency’}  
 

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