Inband signaling and m-blocks

GNU Radio
1

Hi,

I have a couple of basic questions regarding USRP inband signaling and
m-blocks.

  1. Should these two be used together, or are they separate, eg, can i
    use inband signaling with standard blocks?

  2. There is a brief description of inband signling in the trank; is
    there a simple example that i can look up to see how it works in
    practice.

I have in mind something really simple: I want to build a transmitter
that transmits a sinusoid or nothing in PRECICELY specified time
intervals; thus my interest in inband signaling.
When I understand how to do that I want to build a frequency hopping
transmitter/receiver…

Thanks
Achilleas