Preliminary questions to a witness to establish admissibility of evidence i.e. "laying foundation" for admissibility. Fed.Evid.R.104 (Blacks Law dictionary)
In the previous lesson the prosecutor presented foundation as to the evidence by having the officer testify as to the calibration and accuracy of the radar gun. That evidence now is admissible and the court will rely on it to find you guilty, unless you use challenge that foundation to make that evidence inadmissible.
If you correctly challenge that foundation or shed legal doubt as to the accuracy of the evidence presented you will win. If not, you will loose.
The Burdon is upon the party bringing forth the evidence to lay the foundation. In a speeding ticket trial that Burdon is upon the prosecution. When you blow holes into the foundation it is up to the prosecution to try to repair those holes. If they can't then the foundation crumbles and the evidence becomes either inadmissible or incompetent for the basis of a conviction.
Take the testimony from the previous page where the Officer opens the door to challenging the tuning forks by stating that he used two tuning forks for calibration. When cross examined you ask for the certificate certifying their last accuracy check by a facility approved to do such checks. That certificate is a requirement in the case law of St. Louis v. Boecker. If he can't produce that certificate, the ruling from the high court in Boecker makes the accuracy check using the tuning forks inadmissible. If the accuracy check becomes inadmissible the speed readings from the radar gun becomes inadmissible. If the speed readings are inadmissible there is no longer any evidence against you and the Judge has no choice but to dismiss the case.
Should he have the certificate the Tipmra teaches you in the Verification Defense how to make that certificate inadmissible. Here are some shortened sample questions to to give you an idea.
Often Imitated but Never Duplicated