Sure, we can. In the attached package, you can find the cellview sandbox.gated_rosc:schematic shown below that models a gated ring oscillator (GRO) with three output phases and arbitrary analog output waveforms. While its input 'en' is high, the model produces a set of periodic waveforms defined by the 'pwl_func' primitives, of which frequency is controlled by the 'freq' input. When 'en' falls low, all the outputs stop moving until 'en' becomes high again.

In fact, this model is a simple extension of the model described in the Q&A posting titled "Q: Modeling a variable-frequency oscillator with arbitrary periodic waveform", utilizing the 'integ_mod' primitive that produces a periodic sawtooth waveform sweeping the range from 0.0 to 1.0. We just added a 'select' primitive to stop the oscillator from advancing when the 'en' input is 0 by setting the input to the 'integ_mod' primitive equal to zero. Also, we added two more 'pwl_func' primitives to produce additional output phases, of which waveform shapes and timing relationships can be expressed using a piecewise-linear format as illustrated below.

The cellview sandbox.tb_gated_rosc:schematic shown below is a simple testbench to demonstrate the operation of this GRO model. It feeds a 'freq' input gradually increasing from 100M to 200M over time and an 'en' input that periodically becomes 0 and disables the oscillation to the GRO model.

And its simulated waveforms are shown below. When the 'en' input is 1, the GRO model produces three oscillating outputs, of which waveforms and timings match to those described by the 'pwl_func' primitives. Also, when the 'en' input is 0, all the GRO outputs stay still at their last values, until 'en' becomes 1 again and the GRO resumes its oscillation.

You can also reset the phase of the GRO model when the 'en' input falls low, instead of holding it constant, by combining the approach outlined in another Q&A posting titled "Q. Generating a sinusoidal signal with a resettable phase". The cellview sandbox.gated_rosc_rst:schematic shown below uses a 'integ_rst' primitive instead of the 'integ_mod' primitive, which re-initializes its output when its 'rst' input becomes 1. But it does not perform a modulo operation, so we added a self-reset loop consisting of 'slice' and 'or_xbit' primitives that resets the output of the 'integ_rst' primitive to 0 whenever it reaches the value of 1.0.

And here are the simulated waveforms using the same testbench (sandbox.tb_gated_rosc:schematic). Just like the first GRO model, this model produces three oscillating outputs when the 'en' input is 1, of which waveforms and timings match to those described by the 'pwl_func' primitives. But it behaves differently when the 'en' input is 0. Instead of holding the last outputs and resuming from them, the oscillator model resets its outputs to fixed values and starts from them when the 'en' input becomes 1.

Attachment: gated_rosc_20240428.tar.gz

Sure, we can. In the attached package, you can find the cellview sandbox.gated_rosc:schematic shown below that models a gated ring oscillator (GRO) with three output phases and arbitrary analog output waveforms. While its input 'en' is high, the model produces a set of periodic waveforms defined by the 'pwl_func' primitives, of which frequency is controlled by the 'freq' input. When 'en' falls low, all the outputs stop moving until 'en' becomes high again.

In fact, this model is a simple extension of the model described in the Q&A posting titled "Q: Modeling a variable-frequency oscillator with arbitrary periodic waveform", utilizing the 'integ_mod' primitive that produces a periodic sawtooth waveform sweeping the range from 0.0 to 1.0. We just added a 'select' primitive to stop the oscillator from advancing when the 'en' input is 0 by setting the input to the 'integ_mod' primitive equal to zero. Also, we added two more 'pwl_func' primitives to produce additional output phases, of which waveform shapes and timing relationships can be expressed using a piecewise-linear format as illustrated below.

The cellview sandbox.tb_gated_rosc:schematic shown below is a simple testbench to demonstrate the operation of this GRO model. It feeds a 'freq' input gradually increasing from 100M to 200M over time and an 'en' input that periodically becomes 0 and disables the oscillation to the GRO model.

And its simulated waveforms are shown below. When the 'en' input is 1, the GRO model produces three oscillating outputs, of which waveforms and timings match to those described by the 'pwl_func' primitives. Also, when the 'en' input is 0, all the GRO outputs stay still at their last values, until 'en' becomes 1 again and the GRO resumes its oscillation.

You can also reset the phase of the GRO model when the 'en' input falls low, instead of holding it constant, by combining the approach outlined in another Q&A posting titled "Q. Generating a sinusoidal signal with a resettable phase". The cellview sandbox.gated_rosc_rst:schematic shown below uses a 'integ_rst' primitive instead of the 'integ_mod' primitive, which re-initializes its output when its 'rst' input becomes 1. But it does not perform a modulo operation, so we added a self-reset loop consisting of 'slice' and 'or_xbit' primitives that resets the output of the 'integ_rst' primitive to 0 whenever it reaches the value of 1.0.

And here are the simulated waveforms using the same testbench (sandbox.tb_gated_rosc:schematic). Just like the first GRO model, this model produces three oscillating outputs when the 'en' input is 1, of which waveforms and timings match to those described by the 'pwl_func' primitives. But it behaves differently when the 'en' input is 0. Instead of holding the last outputs and resuming from them, the oscillator model resets its outputs to fixed values and starts from them when the 'en' input becomes 1.

Attachment: gated_rosc_20240428.tar.gz