This section covers the functions of Spectrum Analysis and Spectrum Analyzer measurements.

This function is used to determine the total power input
into a spectrum analyzer, radio or noise figure meter. It is used to make sure
that the receiver is not overloaded with noise power and operating outside
it’s dynamic range. Input the Temperature in Kelvin, Bandwidth in Hertz, ENR
Excess Noise Ratio of Hot/Cold noise source, PreAmp Gain, DUT Device Under Test
Noise Figure in dBF and Gain in dB. Press **Calculate**
to compute and display. **Clear** to
reset and reenter value to retry and **Close**
to Quit.

Figure 90 – Spectrum Analyzer Input Power

This function is used to determine the Threshold or Minimum
Detectable Signal MDS. It is used to make sure that the signal is detectable.
Input the Temperature in Kelvin, Bandwidth in Hertz, Noise Figure of Receiver in
dBF, Singal Level in dBm and Noise Level in dBm. The output is the Minimum
Detectable Signal in dBm. Press **Calculate**
to compute and display. **Clear** to
reset and reenter value to retry and **Close**
to Quit.

Figure 91 – Spectrum Analyzer Threshold/ Minimum Detectable Signal

This function is used to determine the Eb/No to Signal to
Noise Levels. Input the Eb/No ratio or the Signal to Noise S/N ratio, the Data
Rate in Bits/Sec and the Channel Bandwidth. The Eb/No or the S/n ratio that is
not input will be calculated. Press **Calculate**
to compute and display. **Clear** to
reset and reenter value to retry and **Close**
to Quit.

Figure 92 – Spectrum Analyzer Eb/No to S/N

This function is used to get a rough estimate of the
Spectrum Analyzer sweep time for a trace to complete.
Enter the RBW- Resolution Bandwidth, the VBW – Video Bandwidth, the
Span all in Hertz and the constant of choice. The output is an approximate sweep
time for the spectrum analyzer. The constant can be determined for a spectrum
analyzer by estimating backward to refine the value. I defaulted to the one most
used for Agilent Analyzers. Press **Calculate**
to compute and display. **Clear** to
reset and reenter value to retry and **Close**
to Quit.

You can also calculate the Spectrum Analyzer Sweep Coverage. That is it determines if the sweep parameters of the Spectrum Analyzer must be sufficient for RWB of each receive frequency point must total equal to or greater than the total span bandwidth. This insures that each frequency “bucket” covers every window needed to cover the entire band without any missed coverage for the point to point bandwidth. Enter the Resolution Bandwidth and the Span of the sweep as well as the number of points in the sweep. Press the associated Calculate button and the coverage Pass/Fail and percentage of coverage. Less than 100% means that there are gaps in the point to point bandwidth coverage thru the span.

Figure 93 – Spectrum Analyzer Sweep Time

This function set is to calculate the Power Average of
Signal and Noise to Signal/Noise. There are two functions, one absolute and the
other relative. For the left one add the Signal + noise level and the Noise
Level all in dBm/Hz. In the other function, enter the signal Delta (i.e. Signal
and Noise to Noise Level delta). In either case it will figure the signal error
due to the added noise contribution. Press **Calculate**
to compute and display. **Clear** to
reset and reenter value to retry and **Close**
to Quit.

Figure 94 - Spectrum Analyzer Power Average SN/N Error

This function set is to calculate the Logarithmic Average
of Signal and Noise to Signal/Noise. The function requires the Signal and Noise
Level in dBm, the Delta Signal + Noise to Noise Level. It will figure the CW
Corrected signal level and CW signal error due to the added noise contribution.
Press **Calculate** to compute and
display. **Clear** to reset and reenter
value to retry and **Close** to Quit.

Figure 95 - Spectrum Analyzer Log Average SN/N Error

This section is used to calculate the appropriate
Inter-Modulation Level. Select the desired Inter-modulation order that you wish
to calculate and enter the Fundamental and IM Product levels in dBm. The
Intermod level of that order is calculated for the device. Press **Calculate**
to compute and display. **Clear** to
reset and reenter value to retry and **Close**
to Quit.

This section calculates the Normalized power of two unequal
level signals used in the adjoining Intermod Level calculations. Enter signal
levels 1 and 2 and Press **Calculate** to
compute and display. **Clear** to reset
and reenter value to retry and **Close**
to Quit.

Figure 96 – Spectrum Analysis Intermod Order and Normalize Unequal Power

This function set calculates the Noise Figure in dBF, the DANL/ANL Displayed Average Noise level or Average Noise Level and the Tangential Sensitivity. Enter the Temperature in Kelvin, the bandwidth in Hertz and one of the three values of DANL, Noise Figure or Tangential Sensitivity. It will compute the missing factor.

If the DANL/ANL check box is checked it computes to/from
DANL and unchecked it computes to/from ANL. In the case below I entered the
temperature, bandwidth and checked the DANL box and entered the DANL of
–88dBm/Hz. It calculated the Noise figure and Tangential Sensitivity of the
receiver. Press **Calculate** to compute
and display. **Clear** to reset and
reenter value to retry and **Close** to
Quit.

Figure 97 - Spectrum Analyzer DANL/NF and TSS

Here I entered an ANL of –120dBm/Hz, 290K, 1KHz Bandwidth and unchecked the box. It calculated the Noise Figure and TSS. Also could have entered in either the TSS or the Noise Figure instead of the ANL and it would have figured the other two.

Figure 98 – Spectrum Analyzer ANL/NF and TSS

Crest factor is a measure of the signal cresting due to
random modulation variations and the probabilities of them adding Fourier series
manner to product above average peaks of instantaneous peaks in the signal
range. Enter any two of the three values and press “Calculate” to compute
the remaining value. Press **Calculate**
to compute and display. **Clear** to
reset and reenter value to retry and **Close**
to Quit.

Figure 99 – Spectrum Analyzer Crest Factor

Pulse De-sensitation Factor or PDF is the determining of or using the pulsed duty cycle power average offset that can be applied to help determine signal measured levels from pulsed signals. For the line spectrum enter any two of the three values Time On, Time Period and/or PDF to calculate the missing component. The PDF is the decibel offset that can be added to a CW signal level to correct to what it would measure in a power-integrating sensor as the pulsed average power.

This one uses any three of the four inputs to calculate the
missing value. It will take the Time On, “K” constant factor, the Bandwidth
and/or finally the PDF. Enter any two of the three values on the right function
and/or any three of the four inputs on the right side function and Press **Calculate**
to compute and display. **Clear** to
reset and reenter value to retry and **Close**
to Quit.

Figure 100 – Spectrum Analyzer PDF

This screen helps the operator to compute all the second
and third order Intermodulation components of mixed signals and the mixing
products. Enter Fund1 and Fund2 values in Hz, KHz, MHz, GHz etc. The units on
the calculator being Hz, will scale units to whatever you wish. Press **Calculate**
to compute and display. **Clear** to
reset and reenter value to retry and **Close**
to Quit.

Figure 101 – Spectrum Analyzer Two Tone

This calculator screen has several functions. The first is
to calculate Span, Points and/or RBW Resolution Bandwidth. Using the Spectrum
Analyzer constant of computation (bandwidth integration factor) it will take two
of the three variables Span, Points and/or RBW Resolution Bandwidth and compute
the missing variable. Press the **Calculate**
button on the left to compute this function. **Clear** to reset and reenter value to retry and **Close** to Quit.

This function can be used to compute either the bandwidth
offset or the converted signal integrated power based on the signal and the
bandwidth of integration of that signal. Note assumes flat bandwidth frequency
response of the range of integration. Press the “Calculate “button on the
right to compute this function. Press **Calculate**
to compute and display. **Clear** to
reset and reenter value to retry and **Close**
to Quit.

Figure 102 – Spectrum Analyzer Bandwidth Correction