|
|
|||
|
|
|||
|
From avagotech.com
Schottky diode detectors are used to detect small signals close to the noise level and to monitor large signals well above the noise. From the noise level up to about -20 dBm (Figure 1) the slope of the response curves is constant. This is the square law region. Video receivers usually operate in this range. The diode receives the signal directly from the antenna in most systems, although a preamplifier may be used to improve sensitivity. This type of receiver is used in short range radar or in counter-measure equipment where the sensitivity of the more complicated superheterodyne receiver is not needed.
Above about -10 dBm the slope is closer to linear but may vary about 30% for different values of frequency, diode capacitance, and load resistance. The slope may be controlled by tuning at the proper power level. Linear detection is used in power monitors. In some applications the linearity is important because the detected voltage is a measure of power input.
Products & Services
Analog dBm meters are instruments that measure signal power. They display values on a dial, usually with a needle or moving pointer.
S meters (strength meters, signal-strength meters) measure the strength of signals in communication systems such as receivers and transmitters.
Noise figure meters measure the noise contribution of an amplifier relative to a noise-free amplifier at a reference temperature. For most Ku-band amplifiers, values are expressed in decibels (dB).
VU meters measure the volume (intensity) of analog audio signals. They display signal levels in volume units (VU), a measure of average volume level.
Surface profilometers are contact or non-contact instruments used to measures surface profiles, roughness, waviness and other finish parameters.
Product Announcements
Topics of Interest
Detectors are essentially low sensitivity receivers which function on the basis of direct rectification of the RF signal through the use of a non-linear resistive element – a diode. Generally...
(Read More)
This application note describes the use of the HSMS-2820 in small signal detector applications at 850 MHz. The single series diode (HSMS-2820) has a detection sensitivity [1] of about 30 mV /µW; i.e.,...
(Read More)
The zero bias Schottky diode detector is ideal for RF/ID tag applications where it can be used to fabricate a receiver which consumes no primary power. However, its performance is heavily dependent...
(Read More)
A conventional Schottky diode detector such as the Avago Technologies HSMS-8101 requires no bias for high level input power — above one milliwatt. However, at low levels, a small amount of dc bias is...
(Read More)
At frequencies above a few megahertz, Schottky barriers emit noise at a power level which is half as much as the familiar Johnson noise of a resistor. The presence of series resistance in the diode...
(Read More)
Technical Articles
|
|
