I'm using a bare-bones Pierce oscillator with a 153.6 kHz crystal for a piece of custom instrumentation using a CD4049UBE hex inverting buffer. The crystal output is sent into two sequential stages of buffer on the same IC to deliver nominally square-wave output. The frequency is dead-on according to the frequency counter, but the square wave isn't symmetric. The "duty cycle" shows the output "low" for about 55% of the time and "high" only about 45%. Is there a way to adjust a circuit like this to get a symmetric output?