biquad~ / filtergraph~ - Modulating frequency with cycle~ ?

Hello,

I am trying to modulate [biquad~]'s cutoff frequency through [filtergaph~] with a [cycle~] object .

I've found a way how to do it, but the end result is not what i expected. Here is what i have:

Now here are the problems:
1. The cutoff modulation isn't smooth, if you compare it to traditional filter LFO's , in that patch its way too sharp.
2. When LFO frequency is set higher than 2. , the output sound doesn't seem to recreate that modulation's speed.

Now i tried to use [line] to smooth things out, and that failed. Also, how come [filtergraph~] frequency inlet accepts signal cables(yellow, black ones), but when i try to modulate that inlet with them, it doesn't seem to do anything? I think this my main mistake : i use float cables(black ones) instead of signal cables to modulate the cutoff inlet, but when i try to do it with signal cables it doesn't seem to work.

I hope i make sense,

Cheers