Our third quarter results were highlighted by 32% growth in adjusted earnings per share.
We continue to generate significant revenue momentum throughout the quarter, realizing 9.1% core revenue growth and order growth of just over 20% against the backdrop of strong broad-based demand.
Strong execution and application of FBS helped to generate 325 basis points of core operating margin expansion, along with very strong free cash flow despite widespread supply chain disruption.
In total, we now have almost $750 million of annualized software revenue across the portfolio with double-digit organic growth profile as well as a high share of recurring revenue and high operating margins.
We generated year-over-year total revenue growth of 12%, core growth of 9.1% and orders growth of just over 20% with backlog increasing by 40% year-over-year.
Adjusted operating margin was 22.8%, while adjusted earnings per share with $0.66, representing a year over year increase of 32%.
The strong adjusted operating margin performance helped us to deliver $252 million of free cash flow, which represented 105% conversion of adjusted net earnings.
iOS posted total revenue growth of 16.6% in the third quarter with core growth of 13.1%.
Fluke's performance was highlighted by high teen's revenue growth at Fluke industrial, which also generated order growth of greater than 20%.
Accruent grew by low single digits in the third quarter while seeing strong bookings greater than 20%.
Specifically service channel continues to demonstrate strong momentum in its large enterprise retail business, with several large customer wins in Q3, including Walgreens, which will roll out automation software across their more than 10,000 locations, and the third largest mobile carrier in North America as they transform their facility management program.
The Precision Technology segment posted a total revenue increase of 8.9% in the third quarter, with core growth of 7.7%.
Growth was led by the performance of its mainstream oscilloscope, with a greater than 30% increase supported by new extensions to the six series MSO product line.
Even with the strong execution, given the continued robust pace of demand from its customers, Tektronix increased its backlog by more than 70% versus a year ago.
Moving to Advanced Healthcare Solutions on slide eight, total revenue increased 9.3%, while core revenue increased 4.7%.
In the U.S., the spike in COVID-related hospitalizations, led to a notable decline in elective procedure volumes toward the end of the quarter, resulting in global electric procedures at approximately 88%, of pre-COVID levels for the period.
Census increased in the low 40% range, highlighted by very strong growth in professional services and related hardware.
The company continues to see good early traction from software innovation efforts with 30% growth year-over-year in Q3.
This FBS execution and the continued strength of our software businesses helped deliver adjusted gross margins of 57.3%, in Q3.
This reflects 90 basis points of expansion on a year-over-year basis, as we accelerated to 220 basis points of total price realization.
Q3 adjusted operating profit was 22.8%, reflecting solid execution across the portfolio, including counter measures enacted in the face of ongoing supply chain challenges.
We had strong margin performance across all of our segments, resulting in 325 basis points of core operating margin expansion.
On slide nine, you can see that in the third quarter, we generated $252 million of free cash flow, representing a 105% conversion of adjusted net income.
Free cash flow over the trailing 12 months increased 22% to $991 million.
Our current net leverage is approximately 1.6 times and we expect net leverage to be around 1.3 times at year-end, excluding any additional M&A.
Turning now to the guide on slide 10, we are raising the low end of our full year 2021 adjusted diluted net earnings per share guidance to $2.70, resulting in a range of $2.70 to $2.75 for the year.
This represents a year-over-year growth of 29% to 32% on a continuing operation basis.
This assumes that total revenue growth of 14% to 14.5%, adjusted operating profit margins of 23% to 23.5%.
And an effective tax rate of approximately 14%.
We continue to expect free cash flow conversion to be approximately 105% of adjusted net income for the full year.
We are also initiating fourth quarter adjusted diluted net earnings per share guidance of $0.74 to $0.79, representing year-over-year growth of 6% to 13%.
This assumes total revenue growth of 6.5% to 8.5%, adjusted operating profit margin of 23.5% to 24.5% and an effective tax rate of approximately 15%.
The adjusted diluted net earnings per share guidance also excludes, approximately $12 million of anticipated investments in strategic productivity initiatives that we expect to execute before the end of the year.
For the fourth quarter, we expect free cash flow conversion to be approximately 125% of adjusted net income.

Summary:
Adjusted operating margin was 22.8%, while adjusted earnings per share with $0.66, representing a year over year increase of 32%.
Free cash flow over the trailing 12 months increased 22% to $991 million.
Turning now to the guide on slide 10, we are raising the low end of our full year 2021 adjusted diluted net earnings per share guidance to $2.70, resulting in a range of $2.70 to $2.75 for the year.
We are also initiating fourth quarter adjusted diluted net earnings per share guidance of $0.74 to $0.79, representing year-over-year growth of 6% to 13%.