Wavetek 3001 Instruction Manual page 52

7.
R
epeat steps 4 through 6 with
t
he modu lation meter function switch
set to -AM.
N
ote t h e change i n dB from the -6 dB setting as in step 6 .
8.
R
ecord t
h
e larger of t
h
e
two c
h
a
n
ges o
b
tai
n
e
d
in
steps 6
and
7
on
line 35 of the PT R,
3%
d
istortion to 70% AM (5% to 90% AM) at α
f
r equency ο1 1 kH z.
N ote:
This specification
a
pplies fo r output limits 6+3 dBm. AM is p
ossi b le
above +3 dBm if the pea k of t h e modu lated output
d oes n ot exceed
+13 dBm.
The meas ure ment is m ade wit h α modulation m eter
a
nd α
d
istortion
analyzer wh ich measures the
d
isto rtion of the
d
emodu late d AM from the
mo
d
ulation mete r. The m easu rement i s made at
t
h e m i nim um leveler poi nt
where t he AM
d
isto rtion is no rm ally worst-case .
(2)(6)
1 . Sσt the instr ume n t controls as follows:
FREQUEN CY VERN IER
CA L
Frequ ency selector
520.000 MHz
M
OD ULATIO N MOD E
AM
M
OD ULATIO
N
FREQ 1 kH z
M
OD ULATIO N FM/AM
0% AM
OU T PUT VERN I ER
-7 dB
OU T PUT Step Αττεηυαtπr
0 dBm
2.
Co nn ect the equipment as
s
h own in Fig ure 4-2.
3. Set t h e modu lation meter to rea d %ΑΜ at 520 MHz. Set th e RF in pu t
attenu atio n to 10 d
e, the IF bandwidth 2ο ±400 kH z, the meter response
to fast, the function switch to + ΑΜ ,
t
h e meter ra nge switch to 100, and
t
h e filter bandwi dth to 50 Hz to 15 kH z.
4. Adjust the
M
OD UL ATIO N FM/AM sli de r fo r α modu lation meter
rea ding of 70% AM . Set the mo du lation meter functio n s
w
itch to -AM,
an d
o
bserve the modu lation meter reading.
R ea dj ust the
M
OD UL ATIO N
FM/AM slider until the ave r age of the two mod ulation m eter readings in
+ΑΜ an d -AM p
ositions of the mo du lation meter f unction switch is equ al
to 70% AM,
5. Cali brate the d
isto rtion analyze r and measure t h e d
istortion. The
d
istortio n
s
h ou ld be less t
h
an 3% .
R
eco r d the d
istortion on line 36 of
the PTR .
6. A djust t h e
M
OD UL ATIO N FM/AM slider as in step 4 un til the
average of the mo dulation meter rea di n gs in + ΑΜ and -AM
p
ositio ns
of
t
he mo dulatio n function switch is equal to 90% AM .
7. Cali brate t h e d
istortion analyzer and measure the
d
istortion. The
distortion
s
houl
d
b e less than 5% .
R
ecord
t
h e d
istortion on line 37 of
the
P
TR.