Yes. The 'ilo' primitive models an injection-locked oscillator (ILO) using an advanced concept called “Perturbation Projection Vector (PPV)” and can model various nonlinear behavior of an ILO including the pulling behavior. For more information, please refer to the reference documentation on the 'ilo' primitive and the article, J. Jang and J. Kim, “PPV-based Modeling and Event-Driven Simulation of Injection-Locked Oscillators in SystemVerilog,” IEEE Transactions on Circuits and Systems I, August 2015.

Here is a simple example demonstrating the pulling behavior of an ILO. In this example, an ILO is modeled by the 'ilo' primitive having one injection input and eight phase outputs. In this case, the 'ilo' primitive has the PPV of an 8-phase ring oscillator by default, whose magnitude is scaled by the parameter 'scale' equal to 0.1. The rest of the testbench describes a situation when the ILO has the free-running frequency ('fosc') of 1.05GHz while the injection frequency ('finj') is at 1.0GHz.

`include "xmodel.h"

module tb_ilo ();

    xbit [7:0] out;
    xbit inj_xbit;
    xreal inj;
    xreal freq_out, phase_out;

    parameter real finj = 1.0e9;
    parameter real fosc = 1.05e9;

    ilo           #(.num_in(1), .num_phase(8), .freq('{fosc}), .scale('{0.1}))
                  ILO (.in(inj), .out(out[7:0]), .ctrl(`ground));

    clk_gen       #(.freq(finj))
                  ICLK (inj_xbit);
    transition    #(.value0(-1.0), .value1(1.0))
                  ITRAN (.in(inj_xbit), .out(inj));

    clk_to_freq   IFREQ (.in(out[0]), .out(freq_out));
    clk_to_phase  #(.freq(finj)) IPHASE (.in(out[0]), .out(phase_out));

    initial begin
        $xmodel_dumpfile();
        $xmodel_dumpvars();
    end

endmodule

The simulated waveforms below show the time trajectories of the phase and frequency of the oscillator's output clock 'out[0]'. You can observe the beating notes in the phase and frequency trajectories. This is the pulling behavior, which happens when the injection frequency is close to the free-running frequency of the oscillator but not close enough to achieve a lock.

On the other hand, when the free-running frequency of the oscillator is closer to the injection frequency, the oscillator can achieve an injection lock. The waveforms below show the simulated phase and frequency trajectories of the oscillator when its free-running frequency ('fosc') is at 0.98, 0.99, 1.0, 1.01, and 1.02GHz, respectively. You can obtain these waveforms by using the '--sweep' option of the 'xmodel' launcher script.

xmodel tb_ilo.sv --top tb_ilo --simtime 100ns \
       --sweep tb_ilo.fosc=0.98G,0.99G,1.0G,1.01G,1.02G

You can observe that when the injection frequency is close enough to the free-running frequency of the oscillator, the phase and frequency of the oscillator converge to the steady-state values. In particular, the frequency of the oscillator becomes equal to the frequency of the injection input. On the other hand, the phase of the oscillator may not be exactly equal to that of the injection input, when there is a difference between the free-running frequency and the injection frequency.

Yes. The 'ilo' primitive models an injection-locked oscillator (ILO) using an advanced concept called “Perturbation Projection Vector (PPV)” and can model various nonlinear behavior of an ILO including the pulling behavior. For more information, please refer to the reference documentation on the 'ilo' primitive and the article, J. Jang and J. Kim, “PPV-based Modeling and Event-Driven Simulation of Injection-Locked Oscillators in SystemVerilog,” IEEE Transactions on Circuits and Systems I, August 2015.

Here is a simple example demonstrating the pulling behavior of an ILO. In this example, an ILO is modeled by the 'ilo' primitive having one injection input and eight phase outputs. In this case, the 'ilo' primitive has the PPV of an 8-phase ring oscillator by default, whose magnitude is scaled by the parameter 'scale' equal to 0.1. The rest of the testbench describes a situation when the ILO has the free-running frequency ('fosc') of 1.05GHz while the injection frequency ('finj') is at 1.0GHz.

`include "xmodel.h"

module tb_ilo ();

    xbit [7:0] out;
    xbit inj_xbit;
    xreal inj;
    xreal freq_out, phase_out;

    parameter real finj = 1.0e9;
    parameter real fosc = 1.05e9;

    ilo           #(.num_in(1), .num_phase(8), .freq('{fosc}), .scale('{0.1}))
                  ILO (.in(inj), .out(out[7:0]), .ctrl(`ground));

    clk_gen       #(.freq(finj))
                  ICLK (inj_xbit);
    transition    #(.value0(-1.0), .value1(1.0))
                  ITRAN (.in(inj_xbit), .out(inj));

    clk_to_freq   IFREQ (.in(out[0]), .out(freq_out));
    clk_to_phase  #(.freq(finj)) IPHASE (.in(out[0]), .out(phase_out));

    initial begin
        $xmodel_dumpfile();
        $xmodel_dumpvars();
    end

endmodule

The simulated waveforms below show the time trajectories of the phase and frequency of the oscillator's output clock 'out[0]'. You can observe the beating notes in the phase and frequency trajectories. This is the pulling behavior, which happens when the injection frequency is close to the free-running frequency of the oscillator but not close enough to achieve a lock.

On the other hand, when the free-running frequency of the oscillator is closer to the injection frequency, the oscillator can achieve an injection lock. The waveforms below show the simulated phase and frequency trajectories of the oscillator when its free-running frequency ('fosc') is at 0.98, 0.99, 1.0, 1.01, and 1.02GHz, respectively. You can obtain these waveforms by using the '--sweep' option of the 'xmodel' launcher script.

xmodel tb_ilo.sv --top tb_ilo --simtime 100ns \
       --sweep tb_ilo.fosc=0.98G,0.99G,1.0G,1.01G,1.02G

You can observe that when the injection frequency is close enough to the free-running frequency of the oscillator, the phase and frequency of the oscillator converge to the steady-state values. In particular, the frequency of the oscillator becomes equal to the frequency of the injection input. On the other hand, the phase of the oscillator may not be exactly equal to that of the injection input, when there is a difference between the free-running frequency and the injection frequency.