PORTMOD_F is a modulated carrier source. The frequency components of the modulated signal are specified by a data file under the Data Files node in the Project Browser.
|Z||Termination impedance||Resistance||50 ohm|
|Pwr||Available power||DB Power||0 dBm|
|NET||Modulated signal file name||String||"M"|
|PIN_ID||Name identifier for pin||Text|
FRes. If empty, an attempt is made to determine frequency resolution from the data file. The frequency resolution can be declared in the data file by using the FREQ tag. For example:
WINDOW. Window that can be applied to the data. Choices are NONE, DEFAULT, TRIANG, HANN, HAMM and BLACK.
PORTMOD_F is a modulated carrier source. The carrier is centered at the project frequency (or nonlinear frequency); the available signal power is given by Pwr; the port impedance is given by Z; and the frequency resolution (resolution bandwidth) of the modulation signal (the complex envelope) is given by Fres.
When using the PORTMOD_F source, you are performing a two-tone simulation. Tone 1 is the center frequency of the modulation and Tone 2 defines the modulation signal tones. You must make sure to set up enough tone-two harmonics to properly capture all the modulation tones.
The modulation signal is specified in the data file referred to by the NET parameter. Currently, you must type the name of the NET parameter with quotes for it to be recognized. The file must be imported into the Cadence® AWR Design Environment® software as a text data file type. The file specifies the frequency components of the complex envelope as follows:
The magnitude of the frequency components is expressed in dBm and is placed in the first column.
The phase of the frequency components is expressed in degrees and is placed in the second column.
The components are specified in the order of increasing frequency.
If the envelope spectrum is non-symmetric, the file should include the tag SPECTRUM=DOUBLE_SIDED. If the envelope spectrum is symmetric, you can choose to specify only the right-hand side of the spectrum by including the tag SPECTRUM=CONJ_SYM.
The frequency components, as specified in the signal file, are scaled so that the total power is equal to Pwr. You do not, therefore, need to be concerned with the scaling of the signal components.
The following is a portion of a modulated signal data file for a square wave. When used with PORTMOD_F this generates a pulsed RF source with 50% duty cycle, where the project frequency defines the RF frequency and FRES defines the square wave period:
SPECTRUM=CONJ_SYM -6.0205999132796 0 -9.9395089618129 92.8125 -6.14e3 0 -19.454005916507 98.4375 -6.14e3 0 -23.835016465249 104.0625 -6.14e3 0 -26.673358097512 109.6875 -6.14e3 0 -28.74344117002 115.3125 -6.14e3 0 -30.344597920947 120.9375 -6.14e3 0 -31.624141340467 126.5625 -6.14e3 0 -32.665282370505 132.1875 -6.14e3 0 -33.519390719192 137.8125 -6.14e3 0 -34.220154921542 143.4375 -6.14e3 0 -34.790597408595 149.0625 -6.14e3 0 -35.246865213854 154.6875 -6.14e3 0 -35.600412484374 160.3125 -6.14e3 0 -35.859314018019 165.9375 -6.14e3 0 -36.029075371558 171.5625 -6.14e3 0 -36.113130638856 177.1875 -6.14e3 0
When this file is used with FRES set to 10 Hz and 32 harmonics set up for tone 2 without limiting any higher order tones, the input power spectrum of this source displays as follows:
You can use the Cadence® AWR® Visual System Simulator™ (VSS) communications and radar systems design software FILE_SNK block to generate the files used by this source. If you use this block, select the Write data file to project tree parameter, set File format to "Microwave Office Signal File", and set Duration to a value long enough to properly capture the signal.
Examples of using the PORTMOD_F source are found in the "Modulation_Signals.emp" example project file.
The port number P is set automatically. If PIN_ID is not empty, text displays on the pin when it is instantiated as a subcircuit.
This element does not have an assigned layout cell. You can assign artwork cells to any element. See “Assigning Artwork Cells to Layout of Schematic Elements” for details.