These share gains and the teams’ execution also helped drive more than 85 basis points of core operating margin improvement in four of our five segments. Our cash flow performance is also very good, resulting in free cash flow to net income conversion ratio of a 128%.
We are encouraged by our increased M&A activity of late, as we’ve announced $3.3 billion of deals across our portfolio in the first nine months of the year. These acquisition will strengthen our dental, life science and diagnostics, environmental and Test & Measurement segments.
Cultivation funnels across our portfolio remained full, giving us confidence in our ability to deploy our substantial M&A capacity in a strategic and disciplined way. So with that as a backdrop, let’s get in to the details of the quarter.
This morning we reported diluted net earnings per share of $0.95, up 13% and representing another record third quarter for Danaher. Revenues grew 4.5% to 4.9 billion, with core revenues up 3%. The positive impact of acquisitions increased revenues by 2%, while currency translation reduced revenues by 50 basis points.
Geographically, high growth markets led the way increasing high single digits. Despite the headlines in China, our businesses grew double digit, led by our T&M Instruments, Gilbarco Veeder-Root, Diagnostics and Dental platforms. Developed markets remained relatively stable and the US and Western Europe both grew low single digits.
Our gross margin expanded 80 basis points or approximately a $140 million to 52.7%. This increase in gross profit enabled us to increase our sales and marketing and R&D by nearly 60 million in the quarter and deliver 70 basis points of core operating margin expansion.
Turning to our five operating segments, Test and measurement revenues increased 1.5%, while core revenues decreased 1%, primarily due to a decline in our communications platform. Reported operating margin declined a 170 basis points, while core operating margins decreased a 115 basis points.
On Monday, you saw that we announced an agreement to combine our communications business with NetScout Systems to create a premier global provider of network management solutions for both carrier and enterprise customers.
We are excited about this transaction which is the culmination of a multi-year discussion with NetScout about working together. This is a powerful opportunity to combine highly complementary businesses in a transaction that we believe will benefit all Danaher and NetScout stakeholders, associates, shareholders and customers alike.
Danaher’s premier troubleshooting, cyber security, and engineering solutions combined with NetScout’s high performance monitoring technologies will give customers access to the most expansive suites of best-in-class product in the industry.
The combined company will offer even greater breadth and depth across both carrier and enterprise networks, expanding opportunity through innovation and growth and improving our customers overall experience.
We anticipate that this transaction will close in 2015, subject to customary closing conditions, including regulatory NetScout shareholder and other approvals. Upon close, our Executive Vice President, Jim Lico will join NetScout’s Board of Directors, while retaining his responsibility to Danaher.
Now back to the results from the quarter, our communications platform core revenues decreased at a double-digit rate. High teens growth in our security solutions business was more than offset by a decline in network management solutions due to spending delays from a wireless carrier customers, primarily in North America.
Despite the revenue decline, we were encouraged by the positive order growth in the platform that we believe will continue for the remainder of the year.
At Arbor demand for Pravail enterprise security products grew more than 50% as IT Security customers continue to rely on Arbor to prevent and mitigate attacks on their networks.
Around the world conducting business has become increasingly virtual, and Arbor is responding with flexible solutions to help customers of all sizes quickly and cost effectively launch or expand best-in-class security solutions.
Fluke Network saw robust demand for its enterprise TruView system and portable network tools which were each up 15%. F Net’s TruView system continues to receive industry recognition and we are honored with the 2014 Communications Solutions Product of the Year Award from the global media company, TMC.
Our instruments platform core revenue increased at low single-digit rate with growth in most major geographies. Fluke core revenues were up mid-single digits representing its highest quarterly growth rate in over three years. Growth was solid across most major product lines, led by calibration and biomedical which each increased double-digits.
Distribution [sell-out] [ph] remained strong globally, particularly in North America and China, where growth was mid-single digit or better. Fluke plans to build on this momentum by launching Fluke Connect in China later this month.
At Tektronix core sales were up slightly, with modest growth in point of sales in North America and healthy demand for power supplies and oscilloscopes in China.
Turning to our environmental segment, revenues increased 10.5% with core revenues up 5%. Segment core operating margin improved 85 basis points with reported operating margin down 30 basis points due to the dilutive effect of recent acquisitions. Water quality core revenues increased at a mid-single digit rate with strength in analytical instrumentation and chemical treatment solutions.
Hach executed well in a temperate municipal spending environment driving above market growth in both North America and Europe. Sales also healthy in China growing double-digits. This month, Hach will launch the SL1000 Portable Parallel Analyzer or PPA, a breakthrough system that dramatically streamlines water quality testing.