Anritsu 373XXA manual Main Lobe Width null \ null in ns =

PERFORMANCE SPECIFICATIONS APPENDIX D

analyzing the most critical compression frequencies of a broadband amplifier.

CH1 : b2/1		CH3 : S21 FWD TRANS
POWER OUT		PHASE
REF = 15.000 dBm		REF = 5.00°
1.000 dB/DIV	CW MODE	2.00°/DIV

Power Out

Phase

-12.00 dBm 5.00000000 GHz CW 8.00 dBm

Shows Power Out and Phase performance as a func- tion of Input Power at a CW frequency.

HIGH SPEED TIME (DISTANCE) DOMAIN

MEASUREMENT CAPABILITY (OPTION 2)

Option 2, High Speed Time (Distance) Domain software al- lows the conversion of reflection or transmission measure- ments from the frequency domain to the time domain.

Measured S-parameter data is converted to the time do- main by application of a Fast Fourier Transform (FFT) us- ing the Chirp Z-Transform technique. Prior to conversion any one of several selectable windowing functions may be applied. Once the data is converted to the time domain, a gating function may be applied to select the data of inter- est. The processed data may then be displayed in the time domain with display start and stop times selected by the user or in the distance domain with display start and stop distance selected by the user. The data may also be con- verted back to the frequency domain with a time gate to view the frequency response of the gated data.

Lowpass Mode: This mode displays a response equiva- lent to the classic TDR (Time Domain Reflectometer) re- sponse of the device under test. Lowpass response may be displayed in either the impulse or step mode. This type of processing requires a sweep over a harmonic series of frequencies and an extrapolated or user-entered DC value. Bandpass Mode: This mode displays a response equiv- alent to the time response of the device under test to a band limited impulse. This type of processing may be used with any arbitrary frequency sweep range, limited only by the test set range or device under test response.

Phasor Impulse Mode: This mode displays a response similar to the Lowpass impulse response, using data taken over an arbitrary (band limited) sweep range. Detailed in- formation, similar to that contained in the lowpass impulse

response may be used to identify the nature of impedance discontinuities in the device under test. Now, with Phasor Impulse, it is possible to characterize complex impedances on band-limited devices.

Windowing: Any one of four window functions may be applied to the initial frequency data, to counteract the ef- fects of processing data with a finite bandwidth. These win- dows provide a range of tradeoffs of main lobe width ver- sus sidelobe level (ringing).

The general type of function used is the Blackman-Harris window with the number of terms being varied from one to four. Typical performance follows:

Types of Window	First Side Lobe	Impulse Width1
(Number of Terms)	Relative to Peak
Rectangular (1)	–13 dB	1.2W
Nominal-Hamming (2)	–43 dB	1.8W
Low Side Lobe,	–67 dB	2.1W
Blackman-Harris (3)
Minimum Side Lobe,	–92 dB	2.7W
Blackman-Harris (4)

1W(Bin Width) = 1/2∆ f sweep width

Example: When ∆ f = 40 MHz to 40 GHz, W = 12.5 ps

When ∆ f = 40 MHz to 65 GHz, W = 7.7 ps

Gating: A selective gating function may be applied to the time domain data to remove unwanted responses, either in a pass-band or reject-band (mask). This gating function may be chosen as the convolution of any of the above win- dow types with a rectangular gate of user defined position and width. The gate may be specified by entering start and stop times or center and span. The gated data may be dis- played in the time domain, or converted back to the fre- quency domain.

Time Domain Display: Data processed to time domain may be displayed as a function of time or as a function of distance, provided the dielectric constant of the transmis- sion media is entered correctly. In the case of dispersive media such as waveguide or microstrip, the true distance to a discontinuity is displayed in the distance mode. The time display may be set to any arbitrary range by specify- ing either the start and stop times or the center time and span. The unaliased (non-repeating) time range is given by the formula:

UnaliasiedRange (ns ) =	Number of Frequency Data Points
	Frequency Sweep Range (GHz )

The resolution is given by the formula:

Main Lobe Width (null \ null) in ns =	kW
	Freq Sweep Range (GHz )

D-10 373XXA MM