Rohde & Schwarz CMW-KM645, Руководство пользователя

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General Description
R&S
®
CMW-KM645
11 User Manual 1173.9740.02 ─ 04
3.4.1 RF Carrier Requirements
The RF signal consists of a carrier frequency-modulated by the composite audio sig-
nal. According to standard IEC 62106, the modulated carrier is transmitted with a maxi-
mum frequency deviation of
±
75 kHz ("Multiplex Deviation,
±
Peak / 2").
See also chapter 3.5.1, "RF Carrier Results" , on page 11.
3.4.2 RF Modulation Requirements
During stereo broadcasts, the RF signal carries the left and right audio channels, used
to form the signals M and S, and the 19 kHz pilot tone. The RDS subcarrier frequency
is locked to the third harmonic of the pilot tone (57 kHz).
According to ITU-R Recommendation BS.450-3 and standard IEC 62106 (for RDS),
the following limits apply:
●
The maximum "Pilot Deviation" is 8 % to 10 % of the maximum frequency deviation
of
±
75 kHz.
●
The RDS subcarrier deviation is from
±
1.0 kHz to
±
7.5 kHz. The recommended
best compromise is
±
2.0 kHz
●
The maximum deviation due to the M and S signals (Audio Deviation) is 90 % of
the maximum frequency deviation of
±
75 kHz.
●
The maximum frequency error of the pilot tone ("Pilot Frequency Error") is
±
2 Hz.
See also chapter 3.5.2, "RF Modulation Results" , on page 13.
3.5 Measurement Results
The results of the "FM Stereo Radio Measurement" are arranged in several groups.
Use the "Display" parameters to select the different views and to change their appear-
ance and contents.
● RF Carrier Results .................................................................................................. 11
● RF Modulation Results ............................................................................................13
● AF Measurement Results ........................................................................................15
● Selecting and Modifying Views ............................................................................... 17
● Common View Elements .........................................................................................17
3.5.1 RF Carrier Results
The "RF Carrier Results" characterize the properties of the modulated RF signal.
Measurement Results
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