Tín hiệu này khá tốt.

• tín hiệu = signal
• này = this
• khá = quite / fairly / rather
• tốt = good

So the structure is:

tín hiệu này = this signal
khá tốt = fairly good / quite good

In Vietnamese, demonstratives like this and that usually come after the noun.

So:

• tín hiệu này = this signal
• tín hiệu đó = that signal

This is normal Vietnamese word order. English says this signal, but Vietnamese says something closer to signal this.

Vietnamese often does not use a separate verb like is in simple descriptive sentences.

So:

• Tín hiệu này khá tốt literally looks like This signal fairly good
• but it naturally means This signal is fairly good

This is very common in Vietnamese when a noun is being described by an adjective.

khá means fairly, quite, or rather. It makes the adjective less strong than very.

Compare:

• tốt = good
• khá tốt = fairly good / quite good
• rất tốt = very good

So khá tốt sounds positive, but a bit more moderate than rất tốt.

Usually it sounds moderately positive.

khá tốt suggests:

• better than just acceptable
• clearly positive
• but not excellent or emphatic

Depending on context, it can feel like:

• pretty good
• quite good
• fairly good

So it is not weakly negative. It is generally a positive assessment.

Here, tốt is an adjective meaning good.

In Vietnamese, adjectives can directly follow the noun phrase and act like the main predicate of the sentence, without needing to be.

So:

• Tín hiệu này tốt = This signal is good
• Tín hiệu này khá tốt = This signal is fairly good

No. khá must come before the adjective it modifies.

Correct:

• Tín hiệu này khá tốt

Incorrect:

• Tín hiệu này tốt khá

A useful pattern is:

noun + demonstrative + degree word + adjective

For example:

• thời tiết này khá đẹp = this weather is quite nice
• món ăn này rất ngon = this dish is very delicious

The tones matter a lot:

• tín has an acute accent: rising tone
• hiệu has a dot below ệ: heavy falling/glottalized tone
• này has a grave accent: low falling tone
• khá has an acute accent: rising tone
• tốt has an acute accent: rising tone

A rough learner-friendly guide:

• tín ≈ teen with a rising tone
• hiệu is harder; the ending is not exactly English, and the tone is heavy and clipped
• này ≈ nye with a low falling tone
• khá ≈ kha with a rise
• tốt ≈ something like toht with a rise

If you want to sound natural, it helps to learn the whole sentence as a rhythm chunk rather than word by word.

Vietnamese does not use articles the way English does.

So tín hiệu can mean:

• signal
• a signal
• the signal

The exact meaning depends on context.

In this sentence, này makes it specific:

• tín hiệu này = this signal

So no article is needed.

Yes.

• Tín hiệu này tốt = This signal is good
• Tín hiệu này khá tốt = This signal is fairly/quite good

Adding khá softens the statement a little and makes it more nuanced.

Yes, it is natural and straightforward.

It could be used in contexts like:

• phone or internet reception
• radio or electronic signals
• measurements or technical discussion

For example, someone checking reception might say:

• Tín hiệu này khá tốt.

It sounds normal, neutral, and practical.