It was another busy week for Australia's top brokers. This has led to the release of a number of broker notes.

Three broker buy ratings that you might want to know more about are summarised below. Here's why brokers think these ASX shares are in the buy zone:

DroneShield Ltd (ASX: DRO)

According to a note out of Shaw and Partners, its analysts have retained their buy rating on this counter drone technology company's shares with a trimmed price target of 90 cents. Shaw and Partners notes that DroneShield released a quarterly update which fell short of its expectations. However, it believes this was driven by a change of government in the United States, which caused delays to tenders being awarded. In light of this, the broker remains very positive on DroneShield and its outlook. It also sees a lot of value in its shares at current levels. The DroneShield share price ended the week at 63 cents.

ResMed Inc. (ASX: RMD)

A note out of Goldman Sachs reveals that its analysts have retained their buy rating on this sleep disorder treatment company's shares with an improved price target of $49.00. According to the note, the broker was impressed with ResMed's performance during the second quarter, noting that global device sales were ~250bps higher and global mask sales broadly in line with consensus estimates. Importantly, Goldman highlights that the strength in US devices sales (+12% over the prior corresponding period) is early evidence that the growing awareness of obstructive sleep apnoea (OSA) from the uptick in consumer wearables and GLP- 1 therapies is translating into demand for ResMed's products. The ResMed share price was fetching $37.69 at Friday's close.

Steadfast Group Ltd (ASX: SDF)

Another note out of Goldman Sachs reveals that its analysts have upgraded this insurance brokerage company's shares to a buy rating with a price target of $6.50. According to the note, Goldman made the move largely on valuation ground. It notes that Steadfast looks relatively cheap versus global peers which are facing similar rate dynamics and below mid cycle multiples. Goldman feels this limits downside risk for investors. And while the broker acknowledges that Steadfast could yet see further premium rate moderation, it feels that these risks and strategic shifts are reflected in its valuation. Furthermore, it highlights that Steadfast offers defensive earnings streams (and EPS growth), which should support its share price. The Steadfast share price ended the week at $5.79.