UNISource Corporation FG-8102, Руководство по эксплуатации

Страница: 20 / 34

2) Considerations
A. The approximate frequency deviation for a given VCF IN signal can be
determined as follows, The 0.1 V change at the VCF IN BNC produces a
frequency change of 1% of the highest frequency obtainable on a given
range. For example(8202), the highest frequency obtainable on the 100 K
range is 200 KHz. One percent of 200 KHz equals 2 KHz. Therefore, 0.1 V
change at the VCF IN BNC will deviate the output frequency 2 KHz on the
100K range. Following table summarizes the frequency deviation versus
VCF IN voltage for all ranges.
HIGHEST FREQ.
OBTAINABLE(Hz)
FREQ. DEVIATION FOR EACH
0.1 VOLT VCF IN CHANGE(Hz)
RANGE
8102 8103 8105 8110 8102 8103 8105 8110
1 2 3 5 10 0.02 0.03 0.05 0.1
10 20 30 50 100 0.2 0.3 0.5 1
100 200 300 500 1k 2 3 5 10
1K 2k 3k 5k 10k 20 30 50 100
10K 20k 30K 50k 100k 200 300 500 1k
100K 200k 300k 300k 1M 2K 3k 5k 10k
1M 2M 3M 5M 10M 20K 30k 50k 100k
Frequency deviation versus VCF IN voltage for each model.
B. For an example(8102), it is assumed that we wish to generate a 455 KHz
signal with FM deviation of ± 15 KHz (30 KHz swing). 1M range will be used
to obtain the 455 KHz carrier with the FREQ. dial set to 0.455. The highest
frequency obtainable on the 1M range is 2 MHz. One percent of 2 MHz is 20
KHz. Our requirement of 30 KHz deviation is 1.5 times greater than 20 KHz
deviation produced by a 0.1 volt VCF IN swing, thus we will use 1.5 times as
much peak-to-peak voltage swing or 0.15 V.
STATED ANOTHER WAY: SUBSTITUTING THIS EXAMPLE:
desired deviation 30 KHz
1% deviation 20 KHz
C. Remember that the value of VCF IN signal is the peak to peak amplitude.
x0.1 V = required VCF IN signal
x 0.1 = 1.5 x 0.1V = 0.15V