Timer Event with GRC(Relationship among Sample Rate, Frequency, Decimation)

GNU Radio
1

Hi
I am using signal source and variable sink to generate a variable with
name” carrier_frequency”.
I am interested to transmit signal at 920 MHz & 2 GHz.
For that purpose, the signal source parameters are as follows:
Sample Rate: 1000
Waveform: Triangle
Frequency:1
Amplitude:2G

The variable source parameters are:
Variable : Carrier frequency
Decimation: 125

What is the relation among Sample rate, Frequency and decimation?
PLEASE GUIDE ME IN THIS REGARD

2

sample_rate/decimation is the rate at which the variable sink block
samples the incoming stream and updates the variable. -Josh