Cts Tone Frequency And Deviation Measurement - Ramsey Electronics COM3010 User Manual

TYPICAL TEST PROCEDURES

3.10.05 CTS Tone Frequency and Deviation Measurement

The COM3010 can accurately measure the frequency and deviation level of CTS sub-audible
tones. CTS tones are typically sent at ±0.75 kHz deviation while voice deviation is normally
set at ±5 kHz. Therefore it is important to mute the microphone or any other audio input
while measuring CTS frequency and deviation.
CTS Tone Measurement
1. Connect a BNC to BNC cable from the –30dBm OUTPUT on the back panel to the RE-
CEIVE IN jack on the front panel. Warning - Do not under any circumstances connect a
transmitter to the RECEIVE IN jack of the COM3010, or damage will result!
2. Connect the transmitter to be tested to the RF OUT jack.
3. Enter the Transmitter Frequency to be tested into the COM3010's RECEIVE field.
Example Frequency : 464.15 MHz :
Property of Ramsey Electronics, Inc.
4. Select the AF frequency counter on the Receive screen lower right field by pressing
Do not reproduce or distribute.
5. Key the radio while muting the microphone audio. The COM3010 will automatically
switch to Power Meter Mode and display the transmitted power in the GENERATE
screen.
6. The CTS frequency information will be displayed in the RECEIVE screen's AF meter
(lower right field) or the user may enter Zoom mode the by pressing
In Zoom mode the AF meter will use the entire Receive screen.
7. Un-key the transmitter when testing is complete.
Note: The AF frequency counter provides an updated value every second with a resolution
accuracy of 1 Hz. After a period of 10 seconds the resolution accuracy will increase to 0.1Hz .
Example: A transmitter has a CTS tone of 123.4Hz. The user keys the radio into the COM3010
as above. The first count will read 123.0Hz, the second, 123.1Hz, the third, 123.2Hz... and
after ten counts, 123.4Hz. That count will remain for the duration of the transmission.
CTS Tone Deviation Measurement
8. Cycle to one of the three Modulation meters (±4 kHz, ±6 kHz FM Deviation Bargraph
Meters, or Digital FM Deviation Meter) by pressing
same field as the AF meter.
9. Key the transmitter and read the deviation measurement.
10. Adjust the transmitter's CTS deviation as specified in the transmitters service manual.
11. Un-key the transmitter when testing is complete.
These meters are in the
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