Also referred to as quota control, it is a method of selecting subjects for a study. The subjects are already chosen for specific characteristics such as age, sex, education, etc.The quota sampling assures the proper proportion of these traits in the group.lso referred to as quota control, it is a method of selecting subjects for a study. The subjects are already chosen for specific characteristics such as age, sex, education, etc.
In contrast, a broadband signal is a signal which does not occupy the lowest range, but instead a higher range, 1MHz to 3MHz, for example. A wire may have only one baseband signal, but it may hold any number of broadband signals, because they can occur anywhere in the spectrum.
The term DXing, in the context of listening to radio signals of any user of the shortwave band, is the activity of monitoring distant stations. In the context of amateur radio operators, the term DXing refers to the two-way communications with a distant station, using shortwave radio frequencies.