The S&P 500 slipped 9% in the past six months, but shares of Keysight Technologies (KEYS -0.26%) didn't contribute to this market sell-off as it gained 16% over the same period. Those gains were thanks to a string of solid results driven by healthy orders for the company's communications equipment.

Keysight might not be a household name, but the company plays a key role in the deployment of faster networks such as 5G and open radio access networks (O-RAN) with the help of its test and measurement tools. And its products gained traction in the fast-growing automotive electronics and semiconductor markets as well.

These catalysts helped Keysight put up solid numbers in recent quarters, and investors rewarded the company's performance with a resilient performance in the stock market. The good part is that its solid order book suggests that its growth is sustainable.

Keysight Technologies is built for long-term growth

Keysight has been growing at a steady pace over the past few years.

KEYS Revenue (TTM) Chart

KEYS revenue (TTM). Data by YCharts. TTM = trailing 12 months.

The trend continued in the third quarter of fiscal 2022 (the three months ending July 31). Keysight's revenue increased 13% year over year to $1.38 billion on a core basis (excluding the impact of currency changes or businesses acquired or divested in the past 12 months). Adjusted net income increased an impressive 31% year over year to $2.01 per share.

Keysight's record revenue and earnings per share can be attributed to the robust growth in both its business segments: communications solutions and electronic industrial solutions. While the communications business was driven by strength in 5G, O-RAN, and high-speed digital applications, as well as cyber, space, and satellite solutions, the demand for semiconductor measurement, automotive, and energy solutions were instrumental in the growth of the electronic industrial segment.

More importantly, Keysight had solid order flow in both businesses last quarter. The company recorded 14% year-over-year growth in orders on a core basis last quarter to $1.46 billion. Orders increased by "strong double digits" for six quarters in a row, CEO Satish Dhanasekaran said on the latest earnings conference call.

Management raised its outlook for the fiscal year. The company anticipates a 9% jump in revenue and a 20% increase in earnings per share in fiscal 2022. Keysight's estimates suggest that its top line would land at $5.38 billion, and earnings are expected at $7.47 per share versus fiscal 2021.

And analysts are confident that Keysight can sustain its double-digit earnings growth over the long run. Consensus estimates suggest that Keysight could register more than 13% annual bottom-line growth for the next five years. That's not surprising because the demand for the company's solutions should remain healthy for years given the markets it is serving.

The 5G infrastructure and O-RAN markets, for instance, are currently in their early phases of growth. Grand View Research estimates that the 5G infrastructure market could register annual growth of 34% through the end of the decade. This explains why the market for 5G test equipment, which is used by telecom carriers to ensure the reliability, security, and speed of their networks, is also set to grow rapidly. Future Market Insights estimates 26% annual growth in this space over the next decade.

Meanwhile, Keysight's automotive revenue nearly doubled over the past couple of years, driven by the growing adoption of electric vehicles and increasing automation. Dhanasekaran seemed confident about the long-term prospects of the automotive business in his remarks on the conference call: "We're very excited by this big trend we see that's going to play out over the next 10 years where automakers are going to increasingly invest in organic R&D capabilities needed to differentiate their platform over others. And that involves software and hardware, and it's a great fit for the broad array of tools that we offer... ."

The valuation makes the stock a solid bet

Keysight stock trades at 27 times trailing earnings, which is a big discount to its five-year average of 51. The forward earnings multiple of 19 indicates an improvement in its bottom line, and we already saw that the company could sustain impressive earnings growth in the long run.

So investors get a good deal even after the stock's impressive rally. Given that it could turn out to be a top tech stock in the long run, investors should consider buying Keysight before it might soar higher and trade at a richer multiple.