The signal generator provides Amplitude Modulation (AM), Frequency Modulation (FM), Phase Modulation (ΦM), and Pulse Modulation (PM) of the output signal using modulating signals from either the internal AM, FM, ΦM, and pulse generators or external sources that are TTL-compatible. FM and ΦM can not be on at the same time; therefore, only the AM, FM or ΦM, and Pulse Modulation modes can be active simultaneously. The following paragraphs provide descriptions and operating instructions for each modulation mode.

The Amplitude Modulation menu provides amplitude modulation of the output signal using a modulating signal from both the internal AM generator and an external source. The signal generator has two AM operating modes: Linear AM and Log AM. In Linear AM mode, sensitivity is continuously variable from 0 %/V to 100 %/V. The amplitude of the RF output changes linearly as the AM input changes. In Log AM mode, sensitivity is continuously variable from 0 dB/V to 25 dB/V. The amplitude of the RF output changes exponentially as the AM input changes.

Press SOURCE to set the source of the modulating signal as Internal or External.

AM SOURCE set to Internal is shown in Figure: Amplitude Modulation Menu.

Press MODULATION | AMPLITUDE | SOURCE | Internal

Linear AM: Sets the modulation depth of the AM signal in the internal AM Linear mode. Depth is continuously variable from 0 %/V to 100 %/V. The amplitude of the RF output changes linearly as the AM input changes.

Logarithmic AM: Sets the modulation depth of the AM signal in the internal AM Log mode. Depth is continuously variable from 0 dB/V to 25 dB/V. The amplitude of the RF output changes exponentially as the AM input changes.

Linear AM: Sensitivity is continuously variable from 0 PCT/V to 100 PCT/V. The amplitude of the RF output changes linearly as the AM input changes.

Logarithmic AM: Sensitivity is continuously variable from 0 dB/V to 25 dB/V. The amplitude of the RF output changes exponentially as the AM input changes.

Press STATE to switch AM on or off. The Internal AM status display will reflect your selection as Internal On.

Press RATE to open the AM Rate parameter, then edit the current value using the cursor control keys, rotary data knob, or enter a new value using the keypad and the appropriate terminator key. The AM rate range is 0.1 Hz to 1 MHz for sine wave and 0.1 Hz to 100 kHz for square, triangle, and ramp waveforms.

Press WAVEFORM to access the Modulation Waveform menu as shown in Figure: AM Modulation WAVEFORM Menu. Set the modulating waveform from the internal AM generator for the internal modulation function as:

For User defined Waveform (Option10), see Waveform Generator (Option 10).

To provide amplitude modulation of the output signal using a modulating signal from an external source, first set up the external signal generator and connect it to the MG362x1A rear panel AM IN BNC connector.

This menu contains the external AM status window showing the current menu selections and the measured AM Depth. The AM depth measurement function measures the voltage of the external modulation signal and calculates the percentage modulation value.

AM SOURCE set to External is shown in Figure: External Amplitude Modulation Menu.

Press MODULATION | AMPLITUDE | SOURCE | External.

Press STATE to switch AM on and off. The External AM status display will display as External On or Off.

Press SENSITIVITY to open the AM Sensitivity parameter, then edit the current value using the cursor control keys, rotary data knob, or enter a new value using the keypad and the appropriate terminator key. The AM Sensitivity range is 0 %/V to 100 %/V in Linear and 0 dB/V to 25 dB/V in Log. To close the open AM Sensitivity parameter, press SENSITIVITY or make another menu selection.

Press DEPTH to open the AM Depth parameter, then edit the current value using the cursor control keys, rotary data knob, or enter a new value using the keypad and the appropriate terminator key.

The two internal FM operating modes are Locked and Unlocked. In the Locked and Unlocked modes, frequency modulation of the output signal is accomplished by summing the modulating signal into the FM control path of the YIG phase-lock loop.

If Locked is set, the YIG phase-locked loop is used in synthesizing the FM signal. If Unlocked is set, the YIG phase-lock loop is disabled and the FM signal is obtained by applying the modulating signal to the tuning coils of the YIG-tuned oscillator.

The (Source-Internal) Frequency Modulation menu is shown in Figure: Internal Frequency Modulation Menu. The (Source-External) Frequency Modulation menu is shown in Figure: External Frequency Modulation Menu.

Press: MODULATION | FREQUENCY

Press SOURCE to set the source of the modulating signal as Internal or External.

FM SOURCE set to Internal is shown in Figure: Internal Frequency Modulation Menu.

Press: MODULATION | FREQUENCY | SOURCE | Internal.

Press SOURCE Internal to select the internal FM generator as the modulating signal source.

Press STATE to switch FM on or off.

Press MODE to set the FM Mode to Low Noise or Wide (Unlocked). Locked sets the YIG phase-locked loop to synthesize the FM signal. If Unlocked is set, the YIG phase-lock loop is disabled and the FM signal is obtained by applying the modulating signal to the tuning coils of the YIG-tuned oscillator.

Press FILTER sets the high pass filter passband start frequency for the FM signal applied to the FM external input. Set DC for DC coupled, 63 Hz for a 63 Hz high pass filter, 1 kHz for a 1 kHz high pass filter as shown in Figure: FM Filter.

Press RATE to open the FM rate parameter, then edit the current value using the cursor control keys, rotary data knob, or enter a new value using the keypad and the appropriate terminator key. The FM rate range for all waveforms is 0.001 Hz to 10 MHz.

Press WAVEFORM to access the Modulation Waveform menu as shown in Figure: Frequency Modulation Waveforms. Set the modulating waveform from the internal FM generator for the internal modulation function as:

Press DEVIATION to open the FM Deviation parameter, then edit the current value using the cursor control keys, rotary data knob, or enter a new value using the keypad and the appropriate terminator key.

The Frequency Modulation SOURCE set to External provides the modulating signal from an external source connected to the rear panel FM IN BNC connector.

This menu contains the external FM status window that shows the current menu selections and the measured FM Deviation (The FM deviation measurement function measures the voltage of the external modulation signal and calculates the peak frequency deviation).

The External FM menu is shown in Figure: External Frequency Modulation Menu.

Press: MODULATION | FREQUENCY | SOURCE | External

Press STATE to switch external FM on and off.

Sets the synthesis mode employed in generating the FM signal as Locked Low-Noise FM or Unlocked FM

If Locked low-noise is set, the YIG phase-locked loop is used in synthesizing the FM signal. If Unlocked is set, the YIG phase-lock loop is disabled and the FM signal is obtained by applying the modulating signal to the tuning coils of the YIG-tuned oscillator.

 

Press FILTER sets the high pass filter passband start frequency for the FM signal applied to the FM external input. Set DC for DC coupled, 63 Hz for a 63 Hz high pass filter, 1 kHz for a 1 kHz high pass filter as shown in Figure: FM Filter.

Press SENSITIVITY sets the FM sensitivity for the external FM function.
The FM Sensitivity range is –420000000 Hz/V to 420000000 Hz/V. (Range is model dependent)

Press DEVIATION to open the FM Deviation parameter, then edit the current value using the cursor control keys, rotary data knob, or enter a new value using the keypad and the appropriate terminator key.

The MG362x1A can provide phase modulation (ΦM) of the output signal using modulating signals from either its internal ΦM generator or an external source.

The MG362x1A has two ΦM operating modes—Narrow ΦM and Wide ΦM. In Narrow ΦM mode, the maximum ΦM deviation is the lesser of ±3 radians or ±5 MHz for DC to 8 MHz rates. In Wide ΦM mode, the maximum ΦM deviation is the lesser of ±400 radians or ±10 MHz for DC to 1 MHz rates.

Press MODULATION | PHASE | SOURCE | Internal

The Internal PHASE modulation menu is shown in Figure: Internal Phase Modulation Menu.

Press to set phase modulation to Low Noise or Wide Deviation as shown in Figure: Phase Mode.

The Low Noise ΦM mode allows a deviation range of 0.00001 radians to 25.1 radians, and a sensitivity range of ±0.00001 RADS/V to ±25.1 RADS/V. The Wide deviation ΦM mode allows a deviation range of 0.001 radians to 3220 radians, and a sensitivity range of -0.001 RADS/V to -3220 RADS/V OR +0.001 RADS/V to +3220 RADS/V.

Press RATE to open the ΦM Rate parameter, then edit the current value using the cursor control keys, rotary data knob, or enter a new value using the keypad and the appropriate terminator key. The ΦM Rate range is 0.0001 Hz to 10 kHz.

Press WAVEFORM to access the Modulation Waveform Selection menu Figure: Phase Wave Selection. This menu displays the modulation waveforms that are available from the ΦM generator.

To provide phase modulation of the output signal using a modulating signal from an external source, first set up the external signal generator and connect it to the MG362x1A rear panel FM IN BNC connector.

Press: MODULATION | PHASE | SOURCE | External

The Phase Modulation set to External is shown in Figure: External Phase Modulation Menu.

This menu contains the external ΦM status window that shows the current menu selections and the measured ΦM deviation (The ΦM deviation measurement function measures the voltage of the external modulation signal and calculates the peak frequency deviation).

Press SENSITIVITY to open the ΦM sensitivity parameter. Edit the current value using the cursor control keys, rotary data knob, or enter a new value using the keypad and the appropriate terminator key. The Low Noise ΦM mode allows a deviation range of 0.00001 radians to 25.1 radians, and a sensitivity range of ±0.0000391 RADS/V to ±25.13 RADS/V. The Wide deviation ΦM mode allows a deviation range of 0.001 radians to 3220 radians, and a sensitivity range of -0.001 RADS/V to -3220 RADS/V OR +0.001 RADS/V to +3220 RADS/V.

The MG362x1A provides pulse modulation of the output signal using modulating signals from either its internal pulse generator or an external source.

The internal pulse generator can be internally triggered, externally triggered, internally and externally triggered with delay. There is also a composite mode in which an external pulse is summed with the internal pulse to pulse modulate the output signal.

The (SOURCE set to Internal) PULSE Modulation menu is shown in Figure: Internal Pulse Menu. The (SOURCE set to External) PULSE Modulation menu is shown in Figure: External Pulse Menu.

Whenever the internal pulse generator is internally triggered, a TTL-compatible signal that is synchronized to the internal pulse modulation output is available at the rear panel PULSE SYNC OUT connector.

Press SOURCE to set the source of the modulating signal as Internal or External.

PULSE Modulation SOURCE set to Internal is shown in Figure: Internal Pulse Menu.

Press MODULATION | PULSE | SOURCE | Internal

The PERIOD and FREQUENCY (PRF) buttons are interactive. Changing one of these parameters will change the other. Edit the current value using the cursor control keys, rotary data knob, or enter a new value using the keypad and the appropriate terminator key. The frequency (PRF) range is 0.6 Hz to 25,000,000 Hz.

Press PERIOD to set the pulse period of the internal pulse generator to the value entered. Selecting Pulse Period represents the pulse period as time. The pulse period range is determined by the pulse generator clock rate. The period range is 1e-07 to 42 seconds.

Pressing the blue chevron in the lower corner of the screen as shown in Figure: Internal Pulse Menu displays the Pulse Width/Delay List menu Figure: Pulse Width-Delay Menu of the current Pulse Width (W1–W4) and Delay parameter settings.

To change the current value of a parameter, use the cursor control keys to select the parameter, then press and enter the current value using the cursor control keys, rotary data knob, or enter a new value using the keypad and the appropriate terminator key. Press a terminator key to close the open parameter.

Press COUNT to type 1 (Single), 2 (Doublet), 3 (Triplet), or 4 (Quadruplet) pulse mode. Pulse COUNT of 3 (Triplet) is shown in Figure: Pulse Count. Press ENTER. The Internal Pulse Status display will show your selection.

Press COUNT to set the number of pulses generated by the internal pulse generator for each period of the pulsed waveform. The internal pulse generator has four pulse modes. Range is 1-4. Set COUNT to display 1 (single), 2 (doublet pulse), 3 (triplet pulse), and 4 (quadruplet pulse). Individual pulse widths WIDTH 1 (W1), WIDTH 2 (W2), WIDTH 3 (W3), and WIDTH 4 (W4)and delays DELAY 1 (D1), DELAY 2 (D2), DELAY 3 (D3), and DELAY 4 (D4) can be set for each of the pulses in a mode as shown in Figure: Pulse Mode.

 

From the additional Internal Pulse Status menu, press TRIGGER to access the Trigger Mode menu display shown in (Figure: Trigger Mode Menu).

This menu provides the triggering mode for the internal pulse generator. Each trigger mode is described in Setting TRIGGER Waveforms and shown in Figure: Modulation Waveforms.

Refer to and the descriptions below for the types of modulation waveforms.

The pulse generator produces pulses at the internal PRF. Single, Doublet, Triplet, or Quadruplet pulse modulation waveforms at the internal pulse repetition rate. Pulse delay is not available in this trigger mode.

an external pulse gates the internal pulse generator on and off. When gated on, the pulse generator produces a single pulse at the internal PRF.

The pulse generator produces Single, Doublet, Triplet, or Quadruplet pulse modulation waveforms at the internal pulse repetition rate.

The pulse generator is triggered by an external trigger to produce Single, Doublet, Triplet, or Quadruplet pulse modulation waveforms. Pulse delay is not available in this trigger mode.

The pulse generator is triggered by an external trigger to produce Single, Doublet, Triplet, or Quadruplet pulse modulation waveforms delayed by pulse delay.

An external pulse triggers the internal pulse generator and also pulse modulates the output signal. The internal pulse generator produces a single pulse delayed by pulse delay1, which also pulse modulates the output signal.

 

Press POLARITY to select the polarity of the signal that turns the RF on during pulse modulation, as follows:

Specifies positive-true operation; a TTL-high level will turn on the RF output signal.

Specifies negative-true operation; a TTL-low level will turn on the RF output signal.

Selects whether the internal pulse generator is triggered on the rising edge (positive) or falling edge (negative) of the external trigger signal.

 

 

To provide pulse modulation of the output signal using a modulating signal from an external source, first set up the external pulse generator and connect it to the MG362x1A rear panel PULSE IN BNC connector.

Press SOURCE from the menu shown in Figure: External Pulse Menu and set to External.

Press: MODULATION | PULSE | SOURCE | External

Press POLARITY and set the polarity of the signal that turns the RF on during pulse modulation.

For proper operation, the period of the external pulse must be greater than the sum of the pulse repetition rate and pulse width of the internal pulse modulation waveform. To prevent relative timing jitter, the external gating pulse source can be synchronized with the internal pulse generator by using the 10 MHz REF OUT signal output (MG362x1A rear panel) as a frequency reference for the external generator.

The MG362x1A provides the pulse train generator option to simulate complex pulse radar signals. Pulse train is a file based data entry. Import an external pulse pattern file either from a USB memory stick or pluggable SDIO card. The external file should accommodate pulse pattern entries up to 2048. Each entry has three parameters: Pulse ON (in µS), Pulse OFF (in µsec) and the number of repetitions up to 65,535. The Pulse Train menu is shown in Figure: Pulse Train Menu.

Set the Polarity to Normal or Inverted as shown in Figure: Pulse Polarity. When set to Inverted the polarity has rising edges and slopes becoming falling edges and slopes. As well, falling edges and slopes become rising edges and slopes.

The MG362x1A supports a file based data entry for functionalities such as List mode as shown in Figure: Pulse Train List Menu, The file format can be imported in to or out of popular spreadsheet programs such as excel. User can edit the entries in the file through the GUI. Each parameter can be edited by selecting the parameter in the list and then entering a value.

The Pulse Train TRIGGER menu is shown in Figure: Pulse Train Trigger Menu.

Press to set the TRIGGER MODE as shown in Figure: Pulse Train Trigger Mode.

 

Pulse Train TRIGGER SOURCE Menu

 

Phase tracking enables up to three MG362x1A units to phase track with a very high degree of stability. Phase tracking provides the following additional rear panel connectors to link internal reference signals together:

The 100 MHz loopback must be connected on the reference synthesizer as shown. The above adjustment of phase will work successfully when generators are set to the same frequency or frequencies that are harmonically related. The frequencies must be set in advance of making all the adjustments of phase and if the frequencies are subsequently changed, then the process of phase adjustment must be repeated.

Once connected as shown in Figure: Phase Tracking Connections of Multiple MG362X1A Instruments, connect an oscilloscope channel to each of the RF outputs from the signal generators to display the initial phase difference between the RF signals. Use the Phase Offset Menu, adjust the phase offset of one of the units to achieve the desired phase relationship as shown on the oscilloscope. Once the desired phase relationship has been achieved, the Phase Offset value may be zeroed. This will not affect the phase shift of the RF output, but will establish the currently set phase as the reference value for all future entries of Phase Offset.