HP 8712ES User Manual page 147

To Search for
Notch Values
NOTE
NOTE
Dedicated Use
maximum power value
center frequency of stop band
notch −n dB point b
notch −n dB point
b
a. The center frequency is defined by the analyzer as the midpoint between the left
and right notch points.
b. Where n is the target value, and the −n dB point is relative to the maximum
response (marker 1).
The notch search function is intended for transmission or power
measurements in log mag format only.
1. To follow along with this example, you will need to connect a notch
filter to the analyzer in place of the bandpass filter shown in
Figure 4-2.
2. Press
MARKER
3. The notch search feature analyzes a notch filter and calculates the
bandwidth, center frequency, and Q (see note below) for the specified
notch level. (The default notch search level is −6 dB.) The resulting
information is displayed in the upper-right corner of the network
analyzer screen. The notch feature puts marker 1 in delta marker
mode. (Delta marker mode is explained later in this chapter.)
Q stands for "quality factor," defined as the ratio of a circuit's resonant
frequency to its bandwidth. Your analyzer calculates Q as the center
frequency divided by the bandwidth.
Each marker's dedicated use is listed in the following table.
shows a −6 dB notch marker search on measurement channel 1.
Dedicated Use of Markers in Notch Search Mode
Measurement Channel 1
a
(left)
(right)
ES User's Guide
All Off Marker Search
marker 1
marker 3
marker 5
marker 6
Using Instrument Functions
Using Markers
Notch .
Figure 4-7
Measurement Channel 2
marker 2
marker 4
marker 7
marker 8
4-13