Communication Concepts 2M 1KW Amateur Application Note User Manual

Page 6

RF Reference Design Data

Freescale Semiconductor

MRFE6VP61K25H MRFE6VP61K25HS 2 Meter Amateur

IMD MEASUREMENT

IMD measurement was done using two signal generator

with a tone spacing of 1 kHz. Quiescent current was set for
2.5 A under 50 volts with no RF signal at input. 2.5 A was
choosen as a good compromise between gain, linearity and
efficiency.

In order to get optimal linearity, a thermal compensation

circuit was used that tracks the quiescent current of the

board over the temperature range (not shown on picture).
Refer to AN1643 RF LDMOS Power Modules for GSM Base
Station Application: Optimum Biasing Circuit

(1)

or the VHF

Broadcast Reference Design for more information.

(2)

The two--tone IMD values are referenced to the peak

envelope power (PEP) and are spaced 1 kHz apart.

Table 5. Two--Tone IMD

out

(W) PEP

IM3--L

IM3--U

IM5--L

IM5--U

IM7--L

IM7--U

IM9--L

IM9--U

100.0

--42.2

--61.3

--64.1

--72.5

--74.4

--85.1

199.5

--42.0

--42.3

--57.8

--59.6

--69.9

--70.6

--75.2

--78.0

399.8

--44.8

--44.0

--50.8

--51.7

--66.6

--68.2

--73.3

--72.1

599.3

--41.7

--41.5

--45.1

--45.5

--68.1

--71.7

--68.1

--68.9

797.1

--33.7

--42.4

--42.2

--56.5

--57.3

--68.5

--65.9

899.8

--30.8

--30.9

--42.0

--41.8

--51.9

--52.4

--68.0

--69.5

997.8

--28.7

--28.6

--42.7

--42.3

--48.6

--48.7

--73.7

--73.4

at e:

3. NOV .20 10

1 4: 48:

Figure 6. 1000 W PEP Two--Tone Spectrum